fix(theming): fix CSS with nested rules parsing when registering a theme

- replace the regex used to split the CSS string with a function that takes into account nested rules
- remove unused `ruleMatchRegex`

Fixes angular#9869

src/core/services/theming/theming.js

@@ -1138,14 +1138,13 @@ function generateAllThemes($injector, $mdTheming) {
   // Expose contrast colors for palettes to ensure that text is always readable
   angular.forEach(PALETTES, sanitizePalette);
 
-  // MD_THEME_CSS is a string generated by the build process that includes all the themable
+  // MD_THEME_CSS is a string generated by the build process that includes all the themeable
   // components as templates
 
   // Break the CSS into individual rules
-  var rules = themeCss
-                  .split(/}(?!([}'";]))/)
-                  .filter(function(rule) { return rule && rule.trim().length; })
-                  .map(function(rule) { return rule.trim() + '}'; });
+  var rules = splitCss(themeCss).map(function(rule) {
+    return rule.trim();
+  });
 
   THEME_COLOR_TYPES.forEach(function(type) {
     rulesByType[type] = '';
@@ -1277,6 +1276,52 @@ function generateAllThemes($injector, $mdTheming) {
       };
     });
   }
+
+  /**
+   * @param {string} themeCss
+   * @returns {[]} a string representing a CSS file that is split, producing an array with a rule
+   *  at each index.
+   */
+  function splitCss(themeCss) {
+    var result = [];
+    var currentRule = '';
+    var openedCurlyBrackets = 0;
+    var closedCurlyBrackets = 0;
+
+    for (var i = 0; i < themeCss.length; i++) {
+      var character = themeCss.charAt(i);
+
+      // Check for content in quotes
+      if (character === '\'' || character === '"') {
+        // Append text in quotes to current rule
+        var textInQuotes = themeCss.substring(i, themeCss.indexOf(character, i + 1));
+        currentRule += textInQuotes;
+
+        // Jump to the closing quote char
+        i += textInQuotes.length;
+      } else {
+        currentRule += character;
+
+        if (character === '}') {
+          closedCurlyBrackets++;
+          if (closedCurlyBrackets === openedCurlyBrackets) {
+            closedCurlyBrackets = 0;
+            openedCurlyBrackets = 0;
+            result.push(currentRule);
+            currentRule = '';
+          }
+        } else if (character === '{') {
+          openedCurlyBrackets++;
+        }
+      }
+    }
+    // Add comments added after last valid rule.
+    if (currentRule !== '') {
+      result.push(currentRule);
+    }
+
+    return result;
+  }
 }
 
 function generateTheme(theme, name, nonce) {

src/core/services/theming/theming.spec.js

@@ -1055,3 +1055,89 @@ describe('md-themable directive', function() {
     expect(el.hasClass('md-default-theme')).toBe(true);
   }));
 });
+
+describe('$mdThemeProvider with custom styles that include nested rules', function() {
+  it('appends the custom styles taking into account nesting', function() {
+    module('material.core', function($mdThemingProvider) {
+      $mdThemingProvider.generateThemesOnDemand(false);
+      var styles =
+          '@media (min-width: 0) and (max-width: 700px) {'
+          + '  .md-THEME_NAME-theme .layout-row {'
+          + '    background-color: "{{primary-500}}";'
+          + '  }'
+          + '  .md-THEME_NAME-theme .layout-column {'
+          + '    color: blue;'
+          + '    font-weight: bold;'
+          + '  }'
+          + '}';
+
+      $mdThemingProvider.registerStyles(styles);
+      $mdThemingProvider.theme('register-custom-nested-styles');
+    });
+
+    inject(function($MD_THEME_CSS) {
+      // Verify that $MD_THEME_CSS is still set to '/**/' in the test environment.
+      // Check angular-material-mocks.js for $MD_THEME_CSS latest value if this test starts to fail.
+      expect($MD_THEME_CSS).toBe('/**/');
+    });
+
+    var compiledStyles =
+        '@media (min-width: 0) and (max-width: 700px) {'
+        + '  .md-register-custom-nested-styles-theme .layout-row {'
+        + '    background-color: rgb(63,81,181);'
+        + '  }'
+        + '  .md-register-custom-nested-styles-theme .layout-column {'
+        + '    color: blue;'
+        + '    font-weight: bold;'
+        + '  }'
+        + '}';
+
+    // Find the string containing nested rules in the head tag.
+    expect(document.head.innerHTML).toContain(compiledStyles);
+  });
+});
+
+describe('$mdThemeProvider with custom styles that include multiple nested rules', function() {
+  it('appends the custom styles taking into account multiple nesting', function() {
+    module('material.core', function($mdThemingProvider) {
+      $mdThemingProvider.generateThemesOnDemand(false);
+      var styles =
+          '@supports (display: bar) {'
+          + '  @media (min-width: 0) and (max-width: 700px) {'
+          + '    .md-THEME_NAME-theme .layout-row {'
+          + '      background-color: "{{primary-500}}";'
+          + '    }'
+          + '    .md-THEME_NAME-theme .layout-column {'
+          + '      color: blue;'
+          + '      font-weight: bold;'
+          + '    }'
+          + '  }'
+          + '}';
+
+      $mdThemingProvider.registerStyles(styles);
+      $mdThemingProvider.theme('register-custom-multiple-nested-styles');
+    });
+
+    inject(function($MD_THEME_CSS) {
+      // Verify that $MD_THEME_CSS is still set to '/**/' in the test environment.
+      // Check angular-material-mocks.js for $MD_THEME_CSS latest value if this test starts to fail.
+      expect($MD_THEME_CSS).toBe('/**/');
+    });
+
+    var compiledStyles =
+        '@supports (display: bar) {'
+        + '  @media (min-width: 0) and (max-width: 700px) {'
+        + '    .md-register-custom-multiple-nested-styles-theme .layout-row {'
+        + '      background-color: rgb(63,81,181);'
+        + '    }'
+        + '    .md-register-custom-multiple-nested-styles-theme .layout-column {'
+        + '      color: blue;'
+        + '      font-weight: bold;'
+        + '    }'
+        + '  }'
+        + '}';
+
+    // Find the string containing nested rules in the head tag.
+    expect(document.head.innerHTML).toContain(compiledStyles);
+  });
+});