Browser Side Text Input State Tracking for OOPIF.

content/browser/renderer_host/render_widget_host_view_base.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 44 matching lines @@
 class SurfaceHittestDelegate;
 }
 
 namespace ui {
 class LatencyInfo;
 }
 
 namespace content {
 class BrowserAccessibilityDelegate;
 class BrowserAccessibilityManager;
+class RenderFrameHostImpl;
 class SyntheticGesture;
 class SyntheticGestureTarget;
 class WebCursor;
 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 {
  public:
   ~RenderWidgetHostViewBase() override;
 
   float current_device_scale_factor() const {
     return current_device_scale_factor_;
   }
 
@@ skipping 35 matching lines @@
   // the renderer.
   void DidReceiveRendererFrame();
 
   // Notification that a resize or move session ended on the native widget.
   void UpdateScreenInfo(gfx::NativeView view);
 
   // Tells if the display property (work area/scale factor) has
   // 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();
 
   //----------------------------------------------------------------------------
   // The following methods can be overridden by derived classes.
 
   // Notifies the View that the renderer text selection has changed.
   virtual void SelectionChanged(const base::string16& text,
                                 size_t offset,
                                 const gfx::Range& range);
 
@@ skipping 34 matching lines @@
 
   // Create a BrowserAccessibilityManager for this view.
   virtual BrowserAccessibilityManager* CreateBrowserAccessibilityManager(
       BrowserAccessibilityDelegate* delegate);
 
   virtual void AccessibilityShowMenu(const gfx::Point& point);
   virtual gfx::Point AccessibilityOriginInScreen(const gfx::Rect& bounds);
   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,
                                      scoped_ptr<cc::CompositorFrame> frame) {}
 
   // This method exists to allow removing of displayed graphics, after a new
   // page has been loaded, to prevent the displayed URL from being out of sync
   // with what is visible on screen.
   virtual void ClearCompositorFrame() = 0;
 
@@ skipping 32 matching lines @@
   // embedded within the RenderWidgetHostViewBase's Surface to the
   // coordinate space of the embedding Surface. Typically this means that a
   // point was received from an out-of-process iframe's RenderWidget and needs
   // to be translated to viewport coordinates for the root RWHV, in which case
   // this method is called on the root RWHV with the out-of-process iframe's
   // SurfaceId.
   virtual void TransformPointToLocalCoordSpace(const gfx::Point& point,
                                                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.
 
   static void GetDefaultScreenInfo(blink::WebScreenInfo* results);
 
   //----------------------------------------------------------------------------
   // The following pure virtual methods are implemented by derived classes.
 
   // Perform all the initialization steps necessary for this object to represent
   // a popup (such as a <select> dropdown), then shows the popup at |pos|.
@@ skipping 10 matching lines @@
   // |scroll_offset| is the scroll offset of the render view.
   virtual void MovePluginWindows(
       const std::vector<WebPluginGeometry>& moves) = 0;
 
   // Sets the cursor to the one associated with the specified cursor_type
   virtual void UpdateCursor(const WebCursor& cursor) = 0;
 
   // 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;
 
   // Notifies the View that the renderer has ceased to exist.
   virtual void RenderProcessGone(base::TerminationStatus status,
                                  int error_code) = 0;
 
   // Tells the View to destroy itself.
   virtual void Destroy() = 0;
 
@@ skipping 149 matching lines @@
   // A buffer containing the text inside and around the current selection range.
   base::string16 selection_text_;
 
   // The offset of the text stored in |selection_text_| relative to the start of
   // the web page.
   size_t selection_text_offset_;
 
   // 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_;
 
   // The orientation of the display the renderer is currently on.
   gfx::Display::Rotation current_display_rotation_;
 
   // Whether pinch-to-zoom should be enabled and pinch events forwarded to the
   // renderer.
   bool pinch_zoom_enabled_;
 
  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);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_