Fix the bug that minimized panel window might steal focus on Mac

chrome/browser/ui/cocoa/panels/panel_window_controller_cocoa.mm

 // 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.
 
 #include "chrome/browser/ui/cocoa/panels/panel_window_controller_cocoa.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/auto_reset.h"
 #include "base/logging.h"
@@ skipping 570 matching lines @@
 - (int)titlebarHeightInScreenCoordinates {
   NSView* titlebar = [self titlebarView];
   return NSHeight([titlebar convertRect:[titlebar bounds] toView:nil]);
 }
 
 // TODO(dcheng): These two selectors are almost copy-and-paste from
 // BrowserWindowController. Figure out the appropriate way of code sharing,
 // whether it's refactoring more things into BrowserWindowUtils or making a
 // common base controller for browser windows.
 - (void)windowDidBecomeKey:(NSNotification*)notification {
+  // Prevent the minimized panel from invoking any activation logic. This is

[Dmitry Titov, 2014/05/16 16:37:38]

I'm not sure I understand the change being made. If the window is receiving
"didBecomeKey", doesn't it mean the OS already has transferred focus to it?
Would it work if we implement -(BOOL)canBecomeKeyWindow and return NO if it is
minimized?

If you are trying to avoid setting a resizable window mask when the window is
minimized, then perhaps this return should be moved to later in this function.
It feels strange not to activate RWHV on windowDidBecomeKey...

[jianli, 2014/05/20 00:56:00]

We do instruct canBecomeKeyWindow  to return NO but it is never called by the
system when the window is already a key window.

I found another way to deactivate a NSWindow programatically. 

+  // because Cocoa does not support deactivating a window and it could still
+  // try to activate the minimized panel window.
+  if (windowShim_->panel()->IsMinimized())
+    return;
+
   // We need to activate the controls (in the "WebView"). To do this, get the
   // selected WebContents's RenderWidgetHostView and tell it to activate.
   if (WebContents* contents = windowShim_->panel()->GetWebContents()) {
     if (content::RenderWidgetHostView* rwhv =
         contents->GetRenderWidgetHostView())
       rwhv->SetActive(true);
   }
 
   windowShim_->panel()->OnActiveStateChanged(true);
 
   // Make the window user-resizable when it gains the focus.
   [[self window] setStyleMask:
       [[self window] styleMask] | NSResizableWindowMask];
 }
 
 - (void)windowDidResignKey:(NSNotification*)notification {
   // If our app is still active and we're still the key window, ignore this
   // message, since it just means that a menu extra (on the "system status bar")
   // was activated; we'll get another |-windowDidResignKey| if we ever really
   // lose key window status.
   if ([NSApp isActive] && ([NSApp keyWindow] == [self window]))
     return;
 
   [self onWindowDidResignKey];
-
-  // Make the window not user-resizable when it loses the focus. This is to
-  // solve the problem that the bottom edge of the active panel does not
-  // trigger the user-resizing if this panel stacks with another inactive
-  // panel at the bottom.
-  [[self window] setStyleMask:
-      [[self window] styleMask] & ~NSResizableWindowMask];
 }
 
 - (void)windowWillStartLiveResize:(NSNotification*)notification {
   // Check if the user-resizing is allowed for the triggering edge/corner.
   // This is an extra safe guard because we are not able to track the mouse
   // movement outside the window and Cocoa could trigger the user-resizing
   // when the mouse moves a bit outside the edge/corner.
   if (![self canResizeByMouseAtCurrentLocation])
     return;
   userResizing_ = YES;
@@ skipping 102 matching lines @@
 - (void)onWindowDidResignKey {
   // We need to deactivate the controls (in the "WebView"). To do this, get the
   // selected WebContents's RenderWidgetHostView and tell it to deactivate.
   if (WebContents* contents = windowShim_->panel()->GetWebContents()) {
     if (content::RenderWidgetHostView* rwhv =
         contents->GetRenderWidgetHostView())
       rwhv->SetActive(false);
   }
 
   windowShim_->panel()->OnActiveStateChanged(false);
+
+  // Make the window not user-resizable when it loses the focus. This is to
+  // solve the problem that the bottom edge of the active panel does not
+  // trigger the user-resizing if this panel stacks with another inactive
+  // panel at the bottom.
+  [[self window] setStyleMask:
+      [[self window] styleMask] & ~NSResizableWindowMask];
 }
 
 - (void)preventBecomingKeyWindow:(BOOL)prevent {
   canBecomeKeyWindow_ = !prevent;
 }
 
 - (void)fullScreenModeChanged:(bool)isFullScreen {
   [self updateWindowLevel];
 
   // If the panel is not always on top, its z-order should not be affected if
@@ skipping 155 matching lines @@
 - (NSRect)contentRectForFrameRect:(NSRect)frameRect {
   NSRect contentRect = [[[self window] contentView] convertRect:frameRect
                                                        fromView:nil];
   contentRect.size.height -= panel::kTitlebarHeight;
   if (contentRect.size.height < 0)
     contentRect.size.height = 0;
   return contentRect;
 }
 
 @end