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 23 matching lines @@
 #include "ui/gfx/display.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/range/range.h"
 #include "ui/surface/transport_dib.h"
 
 class SkBitmap;
 
 struct AccessibilityHostMsg_EventParams;
 struct ViewHostMsg_SelectionBounds_Params;
-struct ViewHostMsg_TextInputState_Params;
+struct TextInputState;
 
 namespace media {
 class VideoFrame;
 }
 
 namespace blink {
 struct WebScreenInfo;
 class WebMouseEvent;
 class WebMouseWheelEvent;
 }
 
 namespace cc {
 class SurfaceHittestDelegate;
 }
 
 namespace ui {
 class LatencyInfo;
 }
 
 namespace content {
 class BrowserAccessibilityDelegate;
 class BrowserAccessibilityManager;
 class RenderWidgetHostViewBaseObserver;
 class SyntheticGesture;
 class SyntheticGestureTarget;
 class WebCursor;
 struct DidOverscrollParams;
 struct NativeWebKeyboardEvent;
+struct TextInputState;
 struct WebPluginGeometry;
 
 // 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 37 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);
 
+  // Text input state as last reported by the RenderWidget.
+  const TextInputState* text_input_state() const {
+    return text_input_state_.get();
+  }
+
+  // Current (cached) value of text input state. It equals text_input_state()
+  // if this is the RWHV of a child frame. If this is a root RWHV, this value
+  // is the cached value of the last reported text input state by either the
+  // root RenderWidget or the RenderWidget of one of the child frames.

[Charlie Reis, 2016/03/09 00:09:33]

This seems like a confusing method to use correctly.  If I call it on the root
RWHV, then it gives me the current TextInputState for the whole tab.  If I call
it on a child RWHV, it gives me the RWHV's own TextInputState, even if that's
not the current one.

That means all call sites would have to check whether they're calling it on the
root RWHV or not (or somehow verify that they aren't calling it for children). 
That seems quite likely to cause bugs.

Maybe there's another way to structure this?  Maybe the cached value should be
stored on another class (WebContentsImpl?) if it's a tab level concept?  Or this
method could assert or return null if called on a child RWHV?

[EhsanK, 2016/03/14 19:58:08]

Thanks for the suggestion. Your point is quite valid. I moved it up to the
WebContentsImpl which obviated the need to have
RenderWidgetHostViewBase::GetFocusedView(). Now there will be a
WebContentsImpl::GetTextInputState() which will return the cached value.

+  const TextInputState* current_text_input_state() const {
+    return cached_text_input_state_;
+  }
+
+  bool ShouldProcessTextInputState();
+
   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 87 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 of the
+  // input since the text input  could be due to a change in the focused
+  // child-frame's (in OOPIF) or the out of process content managed by
+  // BrowserPlugin.
+  // TODO(ekaramad): Make this non-virtual if possible.
+  virtual void TextInputStateChanged(const TextInputState& 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 133 matching lines @@
 
   static void PaintPluginWindowsHelper(
       HWND parent,
       const gfx::Rect& damaged_screen_rect);
 
   // Needs to be called before the HWND backing the view goes away to avoid
   // crashes in Windowed plugins.
   static void DetachPluginsHelper(HWND parent);
 #endif
 
+  // Returns the currently focused RWHV.

[Charlie Reis, 2016/03/09 00:09:33]

Maybe it's worth mentioning how this relates to current_text_input_state() and
when people should call one vs the other?

[EhsanK, 2016/03/14 19:58:08]

It is removed now since the whole logic of getting the state from a focused
frame has moved up to the WebContentsImpl. I have added some comments there.
Done.

+  RenderWidgetHostViewBase* GetFocusedView();
+
   // Whether this view is a popup and what kind of popup it is (select,
   // autofill...).
   blink::WebPopupType popup_type_;
 
   // The background color of the web content.
   SkColor background_color_;
 
   // While the mouse is locked, the cursor is hidden from the user. Mouse events
   // are still generated. However, the position they report is the last known
   // mouse position just as mouse lock was entered; the movement they report
   // indicates what the change in position of the mouse would be had it not been
   // locked.
   bool mouse_locked_;
 
   // Whether we are showing a context menu.
   bool showing_context_menu_;
 
   // 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_;
 
+  // A cached value for the text input state which is used to avoid successive
+  // calls to GetFocusedView() whenever the text input state is required.

[Charlie Reis, 2016/03/09 00:09:33]

Maybe mention whether this is valid on anything but the main RWHV?

[EhsanK, 2016/03/14 19:58:08]

I guess removing it will make it simpler.

+  const TextInputState* cached_text_input_state_;
+
  private:
   void FlushInput();
 
   gfx::Rect current_display_area_;
 
   uint32_t renderer_frame_number_;
 
   base::OneShotTimer flush_input_timer_;
 
   base::ObserverList<RenderWidgetHostViewBaseObserver> observers_;
 
+  // The last reported input state by the RenderWidget.
+  scoped_ptr<TextInputState> text_input_state_;
+
+  // Whether there are changes in text input state which need further
+  // processing.
+  bool text_input_state_changed_;
+
   base::WeakPtrFactory<RenderWidgetHostViewBase> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewBase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_BASE_H_