Browser Side Text Input State Tracking for OOPIF.

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 9a2e25bcc2b04abc937a4dd588c51b04d152236b..4dcd91cbe7e5f205835ee4eeb9b03fead88bc120 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.h
+++ b/content/browser/renderer_host/render_widget_host_view_base.h
@@ -62,6 +62,7 @@ class LatencyInfo;
 namespace content {
 class BrowserAccessibilityDelegate;
 class BrowserAccessibilityManager;
+class RenderFrameHostImpl;
 class SyntheticGesture;
 class SyntheticGestureTarget;
 class WebCursor;
@@ -69,6 +70,8 @@ struct DidOverscrollParams;
 struct NativeWebKeyboardEvent;
 struct WebPluginGeometry;
 
+using TextInputState = ViewHostMsg_TextInputState_Params;

[Charlie Reis, 2016/02/17 06:22:14]

In cases that params are used widely, we tend to go the other way around: define
a struct and then wrap it in the IPC messages file with
IPC_STRUCT_TRAITS_BEGIN/END.  Is that a big change in this case?

[EhsanK, 2016/02/18 05:48:01]

Done. Hopefully I got it right.

+
 // Basic implementation shared by concrete RenderWidgetHostView subclasses.
 class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
                                                 public IPC::Listener {
@@ -124,6 +127,12 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   // changed since the last time.
   bool HasDisplayPropertyChanged(gfx::NativeView view);
 
+  // The current cached text input state which might be different from
+  // text_input_state_ if the view is for a main frame.

[Charlie Reis, 2016/02/17 06:22:14]

I'm confused.  Why would these two differ for the main frame?  (Maybe this needs
a clearer comment for what it represents, if it's not something specific to this
view.)

[EhsanK, 2016/02/18 05:48:01]

|text_input_state_| : the text input state corresponding to a text input field
in this frame (not child frames).

|current_text_input_state()|: |text_input_state_| of the focused frame or child
frame.

For the main frame, we might have to obtain the input state from one of the OOP
child frames.

Whenever a change in input state of a child frame occurs, the top level RWHV
receives a NotifyTextInputStateChanged() and then it will look for the focused
frame to cache its value into |cached_text_input_state_|.

I could remove NotifyTextInputStateChanged() and |cached_text_input_state_| to
make the code simpler to read. But the every time we need to find the text input
state, we might have to traverse the whole frame tree to find the focused frame
and ask for its input state.

+  const TextInputState* current_text_input_state() const {
+    return cached_text_input_state_;
+  }
+
   base::WeakPtr<RenderWidgetHostViewBase> GetWeakPtr();
 
   //----------------------------------------------------------------------------
@@ -178,7 +187,7 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   virtual gfx::AcceleratedWidget AccessibilityGetAcceleratedWidget();
   virtual gfx::NativeViewAccessible AccessibilityGetNativeViewAccessible();
 
-  // Informs that the focused DOM node has changed.
+  // Informs that the  DOM node has changed.

[Charlie Reis, 2016/02/17 06:22:14]

This doesn't seem like a good change to the comment, given that the method is
named FocusedNodeChanged.  Is the actual behavior not about the focused node
anymore?

[EhsanK, 2016/02/18 05:48:01]

Hmmm. I do not have any recollection of changing this. Sorry. Modified by
mistake.

   virtual void FocusedNodeChanged(bool is_editable_node) {}
 
   virtual void OnSwapCompositorFrame(uint32_t output_surface_id,
@@ -231,6 +240,21 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
                                                cc::SurfaceId original_surface,
                                                gfx::Point* transformed_point);
 
+  // This method is excusively called by the owner RenderWidgetHost to inform
+  // the view about a change in the input state which originated in the
+  // corresponding RenderWidget. This state is stored at the RWHV.
+  // Also, this change does not necessarily reflect the current state the input

[Charlie Reis, 2016/02/17 06:22:14]

Typo?  (the current state the input state)

[EhsanK, 2016/02/18 05:48:01]

Done.

+  // state could be due to a change in the focused child-frame's (in OOPIF) or
+  // out of process content managed by BrowserPlugin.
+  // TODO(ekaramad): Make this non-virtual if possible.
+  virtual void TextInputStateChanged(
+      const ViewHostMsg_TextInputState_Params& params);
+
+  // Notifies the top level RenderWidgetHostView or the corresponding
+  // ui::InputMethod of a change in text input state in either this RWHV or one
+  // of the child frame's RWHV.
+  virtual void UpdateTextInputState();
+
   //----------------------------------------------------------------------------
   // The following static methods are implemented by each platform.
 
@@ -261,10 +285,6 @@ 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 ViewHostMsg_TextInputState_Params& params) = 0;
-
   // Cancel the ongoing composition of the input method attached to the view.
   virtual void ImeCancelComposition() = 0;
 
@@ -434,7 +454,6 @@ 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_;
 
@@ -448,12 +467,23 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
  private:
   void FlushInput();
 
+  // Returns the current text input state from all text input elements in this
+  // view or one of the child frame views.
+  const TextInputState* FindCurrentTextInputState();
+
   gfx::Rect current_display_area_;
 
   uint32_t renderer_frame_number_;
 
   base::OneShotTimer flush_input_timer_;
 
+  // The last reported input state from the RenderWidgetHost.
+  scoped_ptr<TextInputState> text_input_state_;
+
+  // The current cached value of input state which could be obtained from
+  // another RWHV.
+  const TextInputState* cached_text_input_state_;
+
   base::WeakPtrFactory<RenderWidgetHostViewBase> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewBase);