Updated the WindowEventTarget interface in ui\base to return a bool from all its methods which indicates whether the message was handled.

This is to ensure that the default handling on the Windows message is performed by the caller
(LegacyRenderWidgetHostHWND).

Most of the changes in this patch are around passing a bool flag to the methods in the WindowEventTarget
interface and passing that information from the LegacyRenderWidgetHostHWND to the message crackers in ATL.

The changes apart from those are as below:-
1. Added a handler for WM_SYSCOMMAND in the LegacyRenderWidgetHostHWND class. This forwards the message to
   the parent. This is needed because there are cases when the LegacyRenderWidgetHostHWND class is of the same
   size as the parent. For e.g. App windows etc. In these cases the LegacyRenderWidgetHostHWND window receives
   non client mouse messages which when defproced result in the WM_SYSCOMMAND message coming in.

2. There are cases when the LegacyRenderWidgetHostHWND is created after the parent is made visible and the
   associated RenderWidget is visible. Added code to make the LegacyRenderWidgetHostHWND hwnd visible.

3. Added a Destroy method to the LegacyRenderWidgetHostHWND class. This method destroys the
window. The instance is destroyed in OnFinalMessage. This
ensures that we don't have issues with the LegacyRenderWidgetHostHWND  instance getting deleted in 
the context of a message and crashes due to us calling SetMsgHandled which dereferences members in the ATL base 
class.

BUG=381609
R=sky

Review URL: https://codereview.chromium.org/349563002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@279269 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 31 insertions, 5 deletions

diff --git a/ui/base/win/window_event_target.h b/ui/base/win/window_event_target.h
index c7bb670..2c74522 100644
--- a/ui/base/win/window_event_target.h
+++ b/ui/base/win/window_event_target.h
@@ -23,42 +23,68 @@ class UI_BASE_EXPORT WindowEventTarget {
   // The |message| parameter identifies the message.
   // The |w_param| and |l_param| values are dependent on the type of the
   // message.
+  // The |handled| parameter is an output parameter which when set to false
+  // indicates that the message should be DefProc'ed.
   // Returns the result of processing the message.
   virtual LRESULT HandleMouseMessage(unsigned int message,
                                      WPARAM w_param,
-                                     LPARAM l_param) = 0;
+                                     LPARAM l_param,
+                                     bool* handled) = 0;
 
   // Handles keyboard events like WM_KEYDOWN/WM_KEYUP, etc.
   // The |message| parameter identifies the message.
   // The |w_param| and |l_param| values are dependent on the type of the
   // message.
+  // The |handled| parameter is an output parameter which when set to false
+  // indicates that the message should be DefProc'ed.
   // Returns the result of processing the message.
   virtual LRESULT HandleKeyboardMessage(unsigned int message,
                                         WPARAM w_param,
-                                        LPARAM l_param) = 0;
+                                        LPARAM l_param,
+                                        bool* handled) = 0;
 
   // Handles WM_TOUCH events.
   // The |message| parameter identifies the message.
   // The |w_param| and |l_param| values are as per MSDN docs.
+  // The |handled| parameter is an output parameter which when set to false
+  // indicates that the message should be DefProc'ed.
   // Returns the result of processing the message.
   virtual LRESULT HandleTouchMessage(unsigned int message,
                                      WPARAM w_param,
-                                     LPARAM l_param) = 0;
+                                     LPARAM l_param,
+                                     bool* handled) = 0;
 
   // Handles scroll messages like WM_VSCROLL and WM_HSCROLL.
   // The |message| parameter identifies the scroll message.
   // The |w_param| and |l_param| values are dependent on the type of scroll.
+  // The |handled| parameter is an output parameter which when set to false
+  // indicates that the message should be DefProc'ed.
   virtual LRESULT HandleScrollMessage(unsigned int message,
                                       WPARAM w_param,
-                                      LPARAM l_param) = 0;
+                                      LPARAM l_param,
+                                      bool* handled) = 0;
 
   // Handles the WM_NCHITTEST message
   // The |message| parameter identifies the message.
   // The |w_param| and |l_param| values are as per MSDN docs.
+  // The |handled| parameter is an output parameter which when set to false
+  // indicates that the message should be DefProc'ed.
   // Returns the result of processing the message.
   virtual LRESULT HandleNcHitTestMessage(unsigned int message,
                                          WPARAM w_param,
-                                         LPARAM l_param) = 0;
+                                         LPARAM l_param,
+                                         bool* handled) = 0;
+
+  // Handles the WM_SYSCOMMAND message
+  // The |message| parameter identifies the message.
+  // The |w_param| and |l_param| values are as per MSDN docs.
+  // The |handled| parameter is an output parameter which when set to false
+  // indicates that the message should be DefProc'ed.
+  // Returns the result of processing the message.
+  virtual LRESULT HandleSysCommand(unsigned int message,
+                                   WPARAM w_param,
+                                   LPARAM l_param,
+                                   bool* handled) = 0;
  protected:
   WindowEventTarget();
   virtual ~WindowEventTarget();