Fixes crash in RemoteWindowTreeHostWin::HandleActivateDesktop

Rather than route this through RemoteWindowTreeHostWin (which can now
be NULL) I'm routing it through ChromeMetroViewerProcessHost. I'm also
adding a NULL check as it may be possible in some code paths for the
host to have been disconnected and therefor NULL.

BUG=374766
TEST=none
R=ananta@chromium.org

Review URL: https://codereview.chromium.org/297713002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@271816 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/lifetime/application_lifetime_win.cc

@@ -19,11 +19,11 @@
 #include "base/files/file_path.h"
 #include "base/path_service.h"
 #include "chrome/browser/metro_utils/metro_chrome_win.h"
+#include "chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.h"
 #include "chrome/browser/shell_integration.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/installer/util/util_constants.h"
 #include "content/public/browser/web_contents.h"
-#include "ui/aura/remote_window_tree_host_win.h"
 #endif
 
 namespace chrome {
@@ -88,7 +88,7 @@ void ActivateDesktopHelper(AshExecutionStatus ash_execution_status) {
   // Actually launching the process needs to happen in the metro viewer,
   // otherwise it won't automatically transition to desktop.  So we have
   // to send an IPC to the viewer to do the ShellExecute.
-  aura::HandleActivateDesktop(path, ash_execution_status == ASH_TERMINATE);
+  HandleActivateDesktop(path, ash_execution_status == ASH_TERMINATE);
 }
 #endif
 

chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.cc

@@ -34,6 +34,7 @@
 #include "content/public/browser/web_contents.h"
 #include "ui/aura/remote_window_tree_host_win.h"
 #include "ui/gfx/win/dpi.h"
+#include "ui/metro_viewer/metro_viewer_messages.h"
 #include "url/gurl.h"
 
 namespace {
@@ -66,11 +67,28 @@ void OpenURL(const GURL& url) {
 
 }  // namespace
 
+void HandleActivateDesktop(const base::FilePath& path, bool ash_exit) {
+  if (ChromeMetroViewerProcessHost::instance()) {
+    ChromeMetroViewerProcessHost::instance()->Send(
+        new MetroViewerHostMsg_ActivateDesktop(path, ash_exit));
+  }
+}
+
+// static
+ChromeMetroViewerProcessHost* ChromeMetroViewerProcessHost::instance_ = NULL;
+
 ChromeMetroViewerProcessHost::ChromeMetroViewerProcessHost()
     : MetroViewerProcessHost(
           content::BrowserThread::GetMessageLoopProxyForThread(
               content::BrowserThread::IO)) {
   chrome::IncrementKeepAliveCount();
+  DCHECK(instance_ == NULL);
+  instance_ = this;
+}
+
+ChromeMetroViewerProcessHost::~ChromeMetroViewerProcessHost() {
+  DCHECK(instance_ == this);
+  instance_ = NULL;
 }
 
 void ChromeMetroViewerProcessHost::OnChannelError() {

chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.h

@@ -7,9 +7,25 @@
 
 #include "win8/viewer/metro_viewer_process_host.h"
 
+namespace base {
+class FilePath;
+}
+
+// Handles the activate desktop command for Metro Chrome Ash.   The |ash_exit|
+// parameter indicates whether the Ash process would be shutdown after
+// activating the desktop.
+void HandleActivateDesktop(const base::FilePath& shortcut, bool ash_exit);
+
 class ChromeMetroViewerProcessHost : public win8::MetroViewerProcessHost {
  public:
   ChromeMetroViewerProcessHost();
+  virtual ~ChromeMetroViewerProcessHost();
+
+  // Returns the singleton ChromeMetroViewerProcessHost instance. This may
+  // return NULL.
+  static ChromeMetroViewerProcessHost* instance() {
+    return instance_;
+  }
 
  private:
   // win8::MetroViewerProcessHost implementation
@@ -23,6 +39,8 @@ class ChromeMetroViewerProcessHost : public win8::MetroViewerProcessHost {
       const base::string16& search_string) OVERRIDE;
   virtual void OnWindowSizeChanged(uint32 width, uint32 height) OVERRIDE;
 
+  static ChromeMetroViewerProcessHost* instance_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeMetroViewerProcessHost);
 };
 

ui/aura/remote_window_tree_host_win.cc

@@ -135,13 +135,6 @@ void HandleSelectFolder(const base::string16& title,
                                                                 on_failure);
 }
 
-void HandleActivateDesktop(const base::FilePath& shortcut,
-                           bool ash_exit) {
-  DCHECK(aura::RemoteWindowTreeHostWin::Instance());
-  aura::RemoteWindowTreeHostWin::Instance()->HandleActivateDesktop(shortcut,
-                                                                   ash_exit);
-}
-
 void HandleMetroExit() {
   DCHECK(aura::RemoteWindowTreeHostWin::Instance());
   aura::RemoteWindowTreeHostWin::Instance()->HandleMetroExit();
@@ -253,14 +246,6 @@ void RemoteWindowTreeHostWin::HandleOpenURLOnDesktop(
   host_->Send(new MetroViewerHostMsg_OpenURLOnDesktop(shortcut, url));
 }
 
-void RemoteWindowTreeHostWin::HandleActivateDesktop(
-    const base::FilePath& shortcut,
-    bool ash_exit) {
-  if (!host_)
-    return;
-  host_->Send(new MetroViewerHostMsg_ActivateDesktop(shortcut, ash_exit));
-}
-
 void RemoteWindowTreeHostWin::HandleMetroExit() {
   if (!host_)
     return;

ui/aura/remote_window_tree_host_win.h

@@ -87,13 +87,6 @@ AURA_EXPORT void HandleSelectFolder(const base::string16& title,
                                     const SelectFolderCompletion& on_success,
                                     const FileSelectionCanceled& on_failure);
 
-// Handles the activate desktop command for Metro Chrome Ash.   The |ash_exit|
-// parameter indicates whether the Ash process would be shutdown after
-// activating the desktop.
-AURA_EXPORT void HandleActivateDesktop(
-    const base::FilePath& shortcut,
-    bool ash_exit);
-
 // Handles the metro exit command.  Notifies the metro viewer to shutdown
 // gracefully.
 AURA_EXPORT void HandleMetroExit();
@@ -131,10 +124,6 @@ class AURA_EXPORT RemoteWindowTreeHostWin
   void HandleOpenURLOnDesktop(const base::FilePath& shortcut,
                               const base::string16& url);
 
-  // The |ash_exit| parameter indicates whether the Ash process would be
-  // shutdown after activating the desktop.
-  void HandleActivateDesktop(const base::FilePath& shortcut, bool ash_exit);
-
   // Notify the metro viewer that it should shut itself down.
   void HandleMetroExit();
 

win8/viewer/metro_viewer_process_host.h

@@ -54,10 +54,10 @@ class MetroViewerProcessHost : public IPC::Listener,
   bool LaunchViewerAndWaitForConnection(
       const base::string16& app_user_model_id);
 
- private:
   // IPC::Sender implementation:
   virtual bool Send(IPC::Message* msg) OVERRIDE;
 
+ private:
   // IPC::Listener implementation:
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void OnChannelError() OVERRIDE = 0;