introduced transparent background option.

plugins/Android/src/net/gree/unitywebview/WebViewPlugin.java

@@ -74,7 +74,7 @@ public boolean IsInitialized() {
         return mWebView != null;
     }
 
-    public void Init(final String gameObject) {
+    public void Init(final String gameObject, final boolean transparent) {
         final WebViewPlugin self = this;
         final Activity a = UnityPlayer.currentActivity;
         a.runOnUiThread(new Runnable() {public void run() {
@@ -126,6 +126,10 @@ public boolean shouldOverrideUrlLoading(WebView view, String url) {
             String databasePath = webView.getContext().getDir("databases", Context.MODE_PRIVATE).getPath(); 
             webSettings.setDatabasePath(databasePath); 
 
+            if (transparent) {
+                webView.setBackgroundColor(0x00000000);
+            }
+
             if (layout == null) {
                 layout = new FrameLayout(a);
                 a.addContentView(

plugins/Mac/Sources/WebView.m

@@ -101,12 +101,15 @@ @interface WebViewPlugin : NSObject
 
 @implementation WebViewPlugin
 
-- (id)initWithGameObject:(const char *)gameObject_ width:(int)width height:(int)height ua:(const char *)ua_
+- (id)initWithGameObject:(const char *)gameObject_ transparent:(BOOL)transparent width:(int)width height:(int)height ua:(const char *)ua_ 
 {
     self = [super init];
     monoMethod = 0;
     webView = [[WebView alloc] initWithFrame:NSMakeRect(0, 0, width, height)];
     webView.hidden = YES;
+    if (transparent) {
+        [webView setDrawsBackground:NO];
+    }
     [webView setAutoresizingMask:(NSViewWidthSizable|NSViewHeightSizable)];
     [webView setPolicyDelegate:(id)self];
     gameObject = [[NSString stringWithUTF8String:gameObject_] retain];
@@ -315,7 +318,7 @@ - (void)render
 typedef void (*UnityRenderEventFunc)(int eventId);
 extern "C" {
 void *_WebViewPlugin_Init(
-    const char *gameObject, int width, int height, BOOL inEditor, const char *ua);
+    const char *gameObject, BOOL transparent, int width, int height, const char *ua, BOOL ineditor);
 void _WebViewPlugin_Destroy(void *instance);
 void _WebViewPlugin_SetRect(void *instance, int width, int height);
 void _WebViewPlugin_SetVisibility(void *instance, BOOL visibility);
@@ -335,13 +338,13 @@ void _WebViewPlugin_Update(void *instance, int x, int y, float deltaY,
 static NSMutableSet *pool;
 
 void *_WebViewPlugin_Init(
-    const char *gameObject, int width, int height, BOOL ineditor, const char *ua)
+    const char *gameObject, BOOL transparent, int width, int height, const char *ua, BOOL ineditor)
 {
     if (pool == 0)
         pool = [[NSMutableSet alloc] init];
 
     inEditor = ineditor;
-    id instance = [[WebViewPlugin alloc] initWithGameObject:gameObject width:width height:height ua:ua];
+    id instance = [[WebViewPlugin alloc] initWithGameObject:gameObject transparent:transparent width:width height:height ua:ua];
     [pool addObject:[NSValue valueWithPointer:instance]];
     return (void *)instance;
 }

plugins/WebViewObject.cs

@@ -77,7 +77,7 @@ public bool IsKeyboardVisible {
 #if UNITY_EDITOR || UNITY_STANDALONE_OSX
     [DllImport("WebView")]
     private static extern IntPtr _WebViewPlugin_Init(
-        string gameObject, int width, int height, bool ineditor, string ua);
+        string gameObject, bool transparent, int width, int height, string ua, bool ineditor);
     [DllImport("WebView")]
     private static extern int _WebViewPlugin_Destroy(IntPtr instance);
     [DllImport("WebView")]
@@ -108,7 +108,7 @@ private static extern void _WebViewPlugin_Update(IntPtr instance,
     private static extern IntPtr GetRenderEventFunc();
 #elif UNITY_IPHONE
     [DllImport("__Internal")]
-    private static extern IntPtr _WebViewPlugin_Init(string gameObject);
+    private static extern IntPtr _WebViewPlugin_Init(string gameObject, bool transparent);
     [DllImport("__Internal")]
     private static extern int _WebViewPlugin_Destroy(IntPtr instance);
     [DllImport("__Internal")]
@@ -136,19 +136,20 @@ void OnApplicationFocus(bool focus)
 #endif
 
 #if UNITY_EDITOR || UNITY_STANDALONE_OSX
-    public void Init(Callback cb = null, string ua = @"Mozilla/5.0 (iPhone; CPU iPhone OS 7_1_2 like Mac OS X) AppleWebKit/537.51.2 (KHTML, like Gecko) Version/7.0 Mobile/11D257 Safari/9537.53")
+    public void Init(Callback cb = null, bool transparent = false, string ua = @"Mozilla/5.0 (iPhone; CPU iPhone OS 7_1_2 like Mac OS X) AppleWebKit/537.51.2 (KHTML, like Gecko) Version/7.0 Mobile/11D257 Safari/9537.53")
 #else
-    public void Init(Callback cb = null)
+    public void Init(Callback cb = null, bool transparent = false)
 #endif
     {
         callback = cb;
 #if UNITY_EDITOR || UNITY_STANDALONE_OSX
         webView = _WebViewPlugin_Init(
             name,
+            transparent,
             Screen.width,
             Screen.height,
-            Application.platform == RuntimePlatform.OSXEditor,
-            ua);
+            ua,
+            Application.platform == RuntimePlatform.OSXEditor);
         // define pseudo requestAnimationFrame.
         EvaluateJS(@"(function() {
             var vsync = 1000 / 60;
@@ -164,10 +165,10 @@ public void Init(Callback cb = null)
         rect = new Rect(0, 0, Screen.width, Screen.height);
         OnApplicationFocus(true);
 #elif UNITY_IPHONE
-        webView = _WebViewPlugin_Init(name);
+        webView = _WebViewPlugin_Init(name, transparent);
 #elif UNITY_ANDROID
         webView = new AndroidJavaObject("net.gree.unitywebview.WebViewPlugin");
-        webView.Call("Init", name);
+        webView.Call("Init", name, transparent);
 #elif UNITY_WEBPLAYER
         Application.ExternalCall("unityWebView.init", name);
 #endif

plugins/iOS/WebView.mm

@@ -35,12 +35,16 @@ @interface WebViewPlugin : NSObject<UIWebViewDelegate>
 
 @implementation WebViewPlugin
 
-- (id)initWithGameObjectName:(const char *)gameObjectName_
+- (id)initWithGameObjectName:(const char *)gameObjectName_ transparent:(BOOL)transparent
 {
     self = [super init];
 
     UIView *view = UnityGetGLViewController().view;
     webView = [[UIWebView alloc] initWithFrame:view.frame];
+    if (transparent) {
+        webView.opaque = NO;
+        webView.backgroundColor = [UIColor clearColor];
+    }
     webView.delegate = self;
     webView.hidden = YES;
     [view addSubview:webView];
@@ -133,7 +137,7 @@ - (void)evaluateJS:(const char *)js
 @end
 
 extern "C" {
-    void *_WebViewPlugin_Init(const char *gameObjectName);
+    void *_WebViewPlugin_Init(const char *gameObjectName, BOOL transparent);
     void _WebViewPlugin_Destroy(void *instance);
     void _WebViewPlugin_SetFrame(void* instace, int x, int y, int width, int height);
     void _WebViewPlugin_SetMargins(
@@ -143,9 +147,9 @@ void _WebViewPlugin_SetMargins(
     void _WebViewPlugin_EvaluateJS(void *instance, const char *url);
 }
 
-void *_WebViewPlugin_Init(const char *gameObjectName)
+void *_WebViewPlugin_Init(const char *gameObjectName, BOOL transparent)
 {
-    id instance = [[WebViewPlugin alloc] initWithGameObjectName:gameObjectName];
+    id instance = [[WebViewPlugin alloc] initWithGameObjectName:gameObjectName transparent:transparent];
     return (__bridge_retained void *)instance;
 }