Change the window level of Mac panels so they don't occlude the IME candidate window.

BUG=114070
TEST=manual

Review URL: https://chromiumcodereview.appspot.com/9836094

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@129044 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 51 insertions, 4 deletions

diff --git a/chrome/browser/ui/panels/panel_browser_window_cocoa.h b/chrome/browser/ui/panels/panel_browser_window_cocoa.h
index 250b4e2..dd3ceac 100644
--- a/chrome/browser/ui/panels/panel_browser_window_cocoa.h
+++ b/chrome/browser/ui/panels/panel_browser_window_cocoa.h
@@ -10,6 +10,8 @@
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/tabs/tab_strip_model_observer.h"
 #include "chrome/browser/ui/panels/native_panel.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
 #include "ui/gfx/rect.h"
 
 class Browser;
@@ -21,7 +23,8 @@ class Panel;
 // interact with this object when it needs to manipulate the window.
 
 class PanelBrowserWindowCocoa : public NativePanel,
-                                public TabStripModelObserver {
+                                public TabStripModelObserver,
+                                public content::NotificationObserver {
  public:
   PanelBrowserWindowCocoa(Browser* browser, Panel* panel,
                           const gfx::Rect& bounds);
@@ -77,6 +80,11 @@ class PanelBrowserWindowCocoa : public NativePanel,
                              bool foreground) OVERRIDE;
   virtual void TabDetachedAt(TabContentsWrapper* contents, int index) OVERRIDE;
 
+  // Overridden from NotificationObserver.
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
   Panel* panel() { return panel_.get(); }
   Browser* browser() const { return browser_.get(); }
 
@@ -128,6 +136,8 @@ class PanelBrowserWindowCocoa : public NativePanel,
   // priority NSWindowLevel, so we distinguish between the two scenarios.
   bool activation_requested_by_browser_;
 
+  content::NotificationRegistrar registrar_;
+
   DISALLOW_COPY_AND_ASSIGN(PanelBrowserWindowCocoa);
 };
 
diff --git a/chrome/browser/ui/panels/panel_browser_window_cocoa.mm b/chrome/browser/ui/panels/panel_browser_window_cocoa.mm
index 3fdb3fd..17defb4 100644
--- a/chrome/browser/ui/panels/panel_browser_window_cocoa.mm
+++ b/chrome/browser/ui/panels/panel_browser_window_cocoa.mm
@@ -17,7 +17,9 @@
 #import "chrome/browser/ui/panels/panel_utils_cocoa.h"
 #import "chrome/browser/ui/panels/panel_window_controller_cocoa.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
+#include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/native_web_keyboard_event.h"
+#include "content/public/browser/notification_source.h"
 
 using content::WebContents;
 
@@ -51,6 +53,10 @@ PanelBrowserWindowCocoa::PanelBrowserWindowCocoa(Browser* browser,
     activation_requested_by_browser_(false) {
   controller_ = [[PanelWindowControllerCocoa alloc] initWithBrowserWindow:this];
   browser_->tabstrip_model()->AddObserver(this);
+  registrar_.Add(
+      this,
+      chrome::NOTIFICATION_PANEL_CHANGED_EXPANSION_STATE,
+      content::Source<Panel>(panel_.get()));
 }
 
 PanelBrowserWindowCocoa::~PanelBrowserWindowCocoa() {
@@ -328,6 +334,14 @@ void PanelBrowserWindowCocoa::TabDetachedAt(TabContentsWrapper* contents,
   [controller_ tabDetached:contents->web_contents()];
 }
 
+void PanelBrowserWindowCocoa::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  DCHECK_EQ(chrome::NOTIFICATION_PANEL_CHANGED_EXPANSION_STATE, type);
+  [controller_ updateWindowLevel];
+}
+
 // NativePanelTesting implementation.
 class NativePanelTestingCocoa : public NativePanelTesting {
  public:
diff --git a/chrome/browser/ui/panels/panel_window_controller_cocoa.mm b/chrome/browser/ui/panels/panel_window_controller_cocoa.mm
index 9f8a309c..c39a28d 100644
--- a/chrome/browser/ui/panels/panel_window_controller_cocoa.mm
+++ b/chrome/browser/ui/panels/panel_window_controller_cocoa.mm
@@ -1042,9 +1042,32 @@ enum {
 - (void)updateWindowLevel {
   if (![self isWindowLoaded])
     return;
-  BOOL onTop = windowShim_->panel()->always_on_top() &&
-               !windowShim_->panel()->manager()->is_full_screen();
-  [[self window] setLevel:(onTop ? NSStatusWindowLevel : NSNormalWindowLevel)];
+  // Make sure we don't draw on top of a window in full screen mode.
+  if (windowShim_->panel()->manager()->is_full_screen() ||
+      !windowShim_->panel()->always_on_top()) {
+    [[self window] setLevel:NSNormalWindowLevel];
+    return;
+  }
+  // If we simply use NSStatusWindowLevel (25) for all docked panel windows,
+  // IME composition windows for things like CJK languages appear behind panels.
+  // Pre 10.7, IME composition windows have a window level of 19, which is
+  // lower than the dock at level 20. Since we want panels to appear on top of
+  // the dock, it is impossible to enforce an ordering where IME > panel > dock,
+  // since IME < dock.
+  // On 10.7, IME composition windows and the dock both live at level 20, so we
+  // use the same window level for panels. Since newly created windows appear at
+  // the top of their window level, panels are typically on top of the dock, and
+  // the IME composition window correctly draws over the panel.
+  // An autohide dock causes problems though: since it's constantly being
+  // revealed, it ends up drawing on top of other windows at the same level.
+  // While this is OK for expanded panels, it makes minimized panels impossible
+  // to activate. As a result, we still use NSStatusWindowLevel for minimized
+  // panels, since it's impossible to compose IME text in them anyway.
+  if (windowShim_->panel()->IsMinimized()) {
+    [[self window] setLevel:NSStatusWindowLevel];
+    return;
+  }
+  [[self window] setLevel:NSDockWindowLevel];
 }
 
 - (void)enableResizeByMouse:(BOOL)enable {