Add an option to not prune the Android AX tree, to preserve more style info.

content/browser/accessibility/browser_accessibility_manager_android.h

Index: content/browser/accessibility/browser_accessibility_manager_android.h
diff --git a/content/browser/accessibility/browser_accessibility_manager_android.h b/content/browser/accessibility/browser_accessibility_manager_android.h
index 38dae1e9a7bb53e0877eab01b5842be9a630cb27..70aaba8a4bb0ea8ce57b7efa3acfddfd639fddfe 100644
--- a/content/browser/accessibility/browser_accessibility_manager_android.h
+++ b/content/browser/accessibility/browser_accessibility_manager_android.h
@@ -48,6 +48,18 @@ class CONTENT_EXPORT BrowserAccessibilityManagerAndroid
   void SetContentViewCore(
       base::android::ScopedJavaLocalRef<jobject> content_view_core);
 
+  // By default, the tree is pruned for a better screen reading experience,
+  // including:
+  //   * If the node has only static text children
+  //   * If the node is focusable and has no focusable children
+  //   * If the node is a heading
+  // This can be turned off to generate a tree that more accurately reflects
+  // the DOM and includes style changes within these nodes.
+  void set_prune_tree_for_screen_reader(bool prune) {
+    prune_tree_for_screen_reader_ = prune;
+  }
+  bool prune_tree_for_screen_reader() { return prune_tree_for_screen_reader_; }
+
   // Implementation of BrowserAccessibilityManager.
   void NotifyAccessibilityEvent(ui::AXEvent event_type,
                                 BrowserAccessibility* node) override;
@@ -145,6 +157,9 @@ class CONTENT_EXPORT BrowserAccessibilityManagerAndroid
   // Handle a hover event from the renderer process.
   void HandleHoverEvent(BrowserAccessibility* node);
 
+  // See docs for set_prune_tree_for_screen_reader, above.
+  bool prune_tree_for_screen_reader_;
+
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManagerAndroid);
 };