[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..402077ccd8f2462b4cb8f8f91a26761093c05807 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.h
+++ b/content/browser/renderer_host/render_widget_host_view_base.h
@@ -21,6 +21,7 @@
 #include "cc/output/compositor_frame.h"
 #include "cc/surfaces/surface_id.h"
 #include "content/browser/renderer_host/event_with_latency_info.h"
+#include "content/browser/renderer_host/text_input_manager.h"
 #include "content/common/content_export.h"
 #include "content/common/input/input_event_ack_state.h"
 #include "content/public/browser/readback_types.h"
@@ -66,14 +67,17 @@ class BrowserAccessibilityManager;
 class RenderWidgetHostViewBaseObserver;
 class SyntheticGesture;
 class SyntheticGestureTarget;
+class TextInputManager;
 class WebCursor;
 struct DidOverscrollParams;
 struct NativeWebKeyboardEvent;
 struct TextInputState;
 
 // Basic implementation shared by concrete RenderWidgetHostView subclasses.
-class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
-                                                public IPC::Listener {
+class CONTENT_EXPORT RenderWidgetHostViewBase
+    : public RenderWidgetHostView,
+      public IPC::Listener,
+      public TextInputManager::Observer {
  public:
   ~RenderWidgetHostViewBase() override;
 
@@ -240,6 +244,9 @@ 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 +272,6 @@ 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;
 
@@ -379,12 +383,23 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   virtual bool IsChildFrameForTesting() const;
   virtual cc::SurfaceId SurfaceIdForTesting() const;
 
+  // TextInputManager::Observer implementation.
+  void OnDestroyingTextInputManager(
+      TextInputManager* text_input_manager) override;

[Charlie Reis, 2016/05/18 20:46:04]

nit: This belongs near the top, under "IPC::Listener implementation."

[EhsanK, 2016/05/24 20:42:45]

Done. This is removed from this class since RenderWidgetHostViewBase is no
longer an observer of TextInputManager (breaking the observer loop as suggested
in your comment on line 24 of "text_input_manager.h").

[Charlie Reis, 2016/05/26 06:22:03]

Thanks, though that isn't what my line 24 comment was about.  I wanted to avoid
having TextInputManager observe RWHV, which is the other direction.

+
  protected:
   // Interface class only, do not construct.
   RenderWidgetHostViewBase();
 
   void NotifyObserversAboutShutdown();
 
+  // Returns a reference to the current instance of TextInputManager. If no
+  // no reference is found, this method tries to obtain one from the

[Charlie Reis, 2016/05/18 20:46:04]

nit: "no no"

[EhsanK, 2016/05/24 20:42:44]

Done.

+  // RenderWidgetHostDelegate. Returns nullptr if no reference exists or
+  // can be obtained. Unless not possible, this method should be used internally

[Charlie Reis, 2016/05/18 20:46:04]

I don't follow the "Unless not possible" part.  Is there a case when it can't be
used?  (You can also rephrase by ending the sentence with "when possible," which
would flow a little better, though I'm still curious about when it wouldn't be.)

[EhsanK, 2016/05/24 20:42:45]

What I meant to say is that, we should always use GetTextInputManager() since it
tries to initialize everything upon the first call. Basically,
|text_input_manager_| is nullptr at first.

However, in RWHVAura we need to dereference |text_input_manager_| in some const
methods. GetTextInputManager() cannot be const, unless we make it and then
initialize |text_input_manager_| by const casting |this|; which would seem
weird.

+  // to obtain TextInputManager.
+  TextInputManager* GetTextInputManager();
+
   // Whether this view is a popup and what kind of popup it is (select,
   // autofill...).
   blink::WebPopupType popup_type_;
@@ -412,7 +427,6 @@ 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 +437,12 @@ 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 can also become nullptr if the top-level
+  // RenderWidgetHostDelegate owning the TextInputManager is destroyed.
+  TextInputManager* text_input_manager_;
+
  private:
   void FlushInput();