From cedca668f68d2c725be621a376dd83abfce3e62f Mon Sep 17 00:00:00 2001
From: Felipe Gomes <felipc@gmail.com>
Date: Tue, 24 Jan 2017 03:07:51 -0200
Subject: [PATCH] Bug 1282484 - Cache the value of PreferFallback() because
 ShouldPlay() is called several times during the load process. r=qDot

MozReview-Commit-ID: DqjCHssaJde
---
 dom/base/nsObjectLoadingContent.cpp | 12 ++++++++++--
 dom/base/nsObjectLoadingContent.h   |  5 +++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/dom/base/nsObjectLoadingContent.cpp b/dom/base/nsObjectLoadingContent.cpp
index 63edefb043a7b..e5ea23ef89225 100644
--- a/dom/base/nsObjectLoadingContent.cpp
+++ b/dom/base/nsObjectLoadingContent.cpp
@@ -666,7 +666,9 @@ nsObjectLoadingContent::nsObjectLoadingContent()
   , mIsStopping(false)
   , mIsLoading(false)
   , mScriptRequested(false)
-  , mRewrittenYoutubeEmbed(false) {}
+  , mRewrittenYoutubeEmbed(false)
+  , mPreferFallback(false)
+  , mPreferFallbackKnown(false) {}
 
 nsObjectLoadingContent::~nsObjectLoadingContent()
 {
@@ -3457,7 +3459,13 @@ nsObjectLoadingContent::HasGoodFallback() {
 
 bool
 nsObjectLoadingContent::PreferFallback(bool aIsPluginClickToPlay) {
-  return FavorFallbackMode(aIsPluginClickToPlay) && HasGoodFallback();
+  if (mPreferFallbackKnown) {
+    return mPreferFallback;
+  }
+
+  mPreferFallbackKnown = true;
+  mPreferFallback = FavorFallbackMode(aIsPluginClickToPlay) && HasGoodFallback();
+  return mPreferFallback;
 }
 
 nsIDocument*
diff --git a/dom/base/nsObjectLoadingContent.h b/dom/base/nsObjectLoadingContent.h
index fe2d687ccd46f..62ec406f99f97 100644
--- a/dom/base/nsObjectLoadingContent.h
+++ b/dom/base/nsObjectLoadingContent.h
@@ -705,6 +705,11 @@ class nsObjectLoadingContent : public nsImageLoadingContent
     // videos.
     bool                        mRewrittenYoutubeEmbed : 1;
 
+    // Cache the answer of PreferFallback() because ShouldPlay is called several
+    // times during the load process.
+    bool                        mPreferFallback : 1;
+    bool                        mPreferFallbackKnown : 1;
+
     nsWeakFrame                 mPrintFrame;
 
     RefPtr<nsPluginInstanceOwner> mInstanceOwner;