[reland] Browser Side Text Input State Tracking for OOPIF (Aura Only)

content/browser/renderer_host/render_widget_host_view_base.h

Index: content/browser/renderer_host/render_widget_host_view_base.h
diff --git a/content/browser/renderer_host/render_widget_host_view_base.h b/content/browser/renderer_host/render_widget_host_view_base.h
index 8eb96897ecc8dc2feca83d74474372a6cdcf1550..24b53564b94439de8033bfcd89e22f013148afd8 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.h
+++ b/content/browser/renderer_host/render_widget_host_view_base.h
@@ -66,6 +66,7 @@ class BrowserAccessibilityManager;
 class RenderWidgetHostViewBaseObserver;
 class SyntheticGesture;
 class SyntheticGestureTarget;
+class TextInputManager;
 class WebCursor;
 struct DidOverscrollParams;
 struct NativeWebKeyboardEvent;
@@ -126,6 +127,12 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   // changed since the last time.
   bool HasDisplayPropertyChanged(gfx::NativeView view);
 
+  // Called by the TextInputManager to notify the view about being removed from
+  // the list of registered views, i.e., TextInputManager is no longer tracking
+  // TextInputState from this view. The RWHV should reset |text_input_manager_|
+  // to nullptr.
+  void DidUnregisterFromTextInputManager(TextInputManager* text_input_manager);
+
   base::WeakPtr<RenderWidgetHostViewBase> GetWeakPtr();
 
   //----------------------------------------------------------------------------
@@ -240,6 +247,9 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
                                                cc::SurfaceId original_surface,
                                                gfx::Point* transformed_point);
 
+  // Updates the state of the input method attached to the view.
+  virtual void TextInputStateChanged(const TextInputState& text_input_state);
+
   //----------------------------------------------------------------------------
   // The following static methods are implemented by each platform.
 
@@ -265,9 +275,6 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   // Indicates whether the page has finished loading.
   virtual void SetIsLoading(bool is_loading) = 0;
 
-  // Updates the state of the input method attached to the view.
-  virtual void TextInputStateChanged(const TextInputState& params) = 0;
-
   // Cancel the ongoing composition of the input method attached to the view.
   virtual void ImeCancelComposition() = 0;
 
@@ -385,6 +392,18 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
 
   void NotifyObserversAboutShutdown();
 
+  // Returns a reference to the current instance of TextInputManager. The
+  // reference is obtained from RenderWidgetHostDelegate. The first time a non-
+  // null reference is obtained , its value is cached in |text_input_manager_|.

[Charlie Reis, 2016/06/02 22:03:29]

nit: No space before comma.

+  // Then this view is registered with TextInputManage (i.e., the instance
+  // |text_input_manager_| referes to). The RWHV will unregister from the
+  // TextInputManager if it is destroyed or if the TextInputManager itself is
+  // destroyed. The unregistration of the RWHV from TextInputManager is
+  // necessary and must be done by explicitly calling
+  // TextInputManager::Unregister. It is safer to use this method rather than
+  // dereferencing |text_input_manager_|.
+  TextInputManager* GetTextInputManager();
+
   // Whether this view is a popup and what kind of popup it is (select,
   // autofill...).
   blink::WebPopupType popup_type_;
@@ -412,7 +431,6 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   // The current selection range relative to the start of the web page.
   gfx::Range selection_range_;
 
- protected:
   // The scale factor of the display the renderer is currently on.
   float current_device_scale_factor_;
 
@@ -423,6 +441,12 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   // renderer.
   bool pinch_zoom_enabled_;
 
+  // A reference to current TextInputManager instance this RWHV is registered
+  // with. This is initially nullptr until the first time the view calls
+  // GetTextInputManager(). It also becomes nullptr when TextInputManager is
+  // destroyed before the RWHV is destroyed.
+  TextInputManager* text_input_manager_;
+
  private:
   void FlushInput();