Make application shortcuts point to app_host.exe, install App Host during app installation.

chrome/browser/extensions/crx_installer.cc

Index: chrome/browser/extensions/crx_installer.cc
diff --git a/chrome/browser/extensions/crx_installer.cc b/chrome/browser/extensions/crx_installer.cc
index d1f2a77c1f21132033696985f1e761549670cf66..c444e9b3b4ca3ceee26d7703e88368b58cf9791b 100644
--- a/chrome/browser/extensions/crx_installer.cc
+++ b/chrome/browser/extensions/crx_installer.cc
@@ -51,6 +51,10 @@
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 
+#if defined(OS_WIN)
+#include "chrome/browser/extensions/app_host_installer_win.h"
+#endif
+
 using content::BrowserThread;
 using content::UserMetricsAction;
 
@@ -508,7 +512,26 @@ void CrxInstaller::CompleteInstall() {
       return;
     }
   }
+#if defined(OS_WIN)

[benwells, 2012/10/03 05:08:43]

This part of the codebase is platform independent. We can get rid of these #if
checks and have this code all generic with some small tweaks. This would then
let us add a similar concept to linux and / or mac later on.

To do this app_host_installer_win.h should become app_host_installer.h, with
it's implementation changing based on what platform we are on (either via #if or
the linker, but #if should be fine for now).

[huangs, 2012/10/03 20:09:47]

Done.

+  if (extension_->is_platform_app()) {
+    // Ensures that App Host is present.
+    // Will call CompleteExtensionInstall() after.
+    // TODO(huangs): Should this be Unretained, or not?
+    app_host_installer_.EnsureAppHostPresentAndCall(
+        base::Bind(&CrxInstaller::CompleteExtensionInstall,
+                   base::Unretained(this)),
+        base::Bind(&CrxInstaller::OnAppHostInstallFailure,
+                   base::Unretained(this)));
+  } else {
+    CompleteExtensionInstall();
+  }
 
+#else
+  CompleteExtensionInstall();
+#endif
+}
+
+void CrxInstaller::CompleteExtensionInstall() {
   // See how long extension install paths are.  This is important on
   // windows, because file operations may fail if the path to a file
   // exceeds a small constant.  See crbug.com/69693 .
@@ -553,6 +576,13 @@ void CrxInstaller::CompleteInstall() {
 
 }
 
+#if defined(OS_WIN)
+void CrxInstaller::OnAppHostInstallFailure() {
+  string16 error = L"Some random error message";

[benwells, 2012/10/03 05:08:43]

Ah, you did say work in progress....

[huangs, 2012/10/03 20:09:47]

Yup.  I moved this routine.

+  ReportFailureFromFileThread(CrxInstallerError(error));
+}
+#endif
+
 void CrxInstaller::ReportFailureFromFileThread(const CrxInstallerError& error) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   if (!BrowserThread::PostTask(