Move app_installer into chromium.

chrome/installer/launcher_support/chrome_launcher_support.cc

Index: chrome/installer/launcher_support/chrome_launcher_support.cc
diff --git a/chrome/installer/launcher_support/chrome_launcher_support.cc b/chrome/installer/launcher_support/chrome_launcher_support.cc
index 9574ae13560cf43a2bf997aae0bd3983127c6bee..8d052a9b88a5efe36a9eed2a21e786147d93379f 100644
--- a/chrome/installer/launcher_support/chrome_launcher_support.cc
+++ b/chrome/installer/launcher_support/chrome_launcher_support.cc
@@ -25,6 +25,9 @@ const wchar_t kBinariesAppGuid[] = L"{4DC8B4CA-1BDA-483e-B5FA-D3C12E15B62D}";
 // Copied from google_chrome_distribution.cc.
 const wchar_t kBrowserAppGuid[] = L"{8A69D345-D564-463c-AFF1-A69D9E530F96}";
 
+// Copied frome google_chrome_sxs_distribution.cc.
+const wchar_t kSxSBrowserAppGuid[] = L"{4ea16ac7-fd5a-47c3-875b-dbf4a2008c20}";
+
 // Copied from util_constants.cc.
 const wchar_t kChromeExe[] = L"chrome.exe";
 const wchar_t kUninstallStringField[] = L"UninstallString";
@@ -99,6 +102,13 @@ base::FilePath FindExeRelativeToSetupExe(const base::FilePath setup_exe_path,
   return base::FilePath();
 }
 
+// Returns the path to an installed SxS chrome.exe at the specified level, if
+// it can be found via Omaha client state.
+base::FilePath GetChromeSxSPathForInstallationLevel(InstallationLevel level) {
+  return FindExeRelativeToSetupExe(
+      GetSetupExeFromRegistry(level, kSxSBrowserAppGuid), kChromeExe);
+}
+
 }  // namespace
 
 base::FilePath GetChromePathForInstallationLevel(InstallationLevel level) {
@@ -115,4 +125,12 @@ base::FilePath GetAnyChromePath() {
   return chrome_path;
 }
 
+base::FilePath GetAnyChromeSxSPath() {
+  base::FilePath path =
+      GetChromeSxSPathForInstallationLevel(USER_LEVEL_INSTALLATION);

[Matt Giuca, 2014/10/30 02:33:07]

Is there a reason this prioritizes user-level installation, whereas
GetAnyChromePath prioritizes system-level?

[Matt Giuca, 2014/10/30 02:55:44]

Just asked the same question on:
https://codereview.chromium.org/685103004
feel free to ignore this and answer it there.

+  if (path.empty())
+    path = GetChromeSxSPathForInstallationLevel(SYSTEM_LEVEL_INSTALLATION);
+  return path;
+}
+
 }  // namespace chrome_launcher_support