Implement GetInstalledFile() in WidevineCdmComponentInstaller.

chrome/browser/component_updater/widevine_cdm_component_installer.cc

Index: chrome/browser/component_updater/widevine_cdm_component_installer.cc
diff --git a/chrome/browser/component_updater/widevine_cdm_component_installer.cc b/chrome/browser/component_updater/widevine_cdm_component_installer.cc
index 8bc3feff3eb36b62cbff0a79e7057ef370cc35b2..eb434ac52f141d4ee2a682a64209d12d958be53c 100644
--- a/chrome/browser/component_updater/widevine_cdm_component_installer.cc
+++ b/chrome/browser/component_updater/widevine_cdm_component_installer.cc
@@ -251,7 +251,22 @@ bool WidevineCdmComponentInstaller::Install(
 
 bool WidevineCdmComponentInstaller::GetInstalledFile(
     const std::string& file, base::FilePath* installed_file) {
-  return false;
+  // Only the CDM is component-updated.
+  if (file != kWidevineCdmFileName)
+    return false;
+
+  if (current_version_.Equals(base::Version(kNullVersion)))
+    return false;  // No CDM has been installed yet.
+
+  base::FilePath installed_cdm_path =
+      GetWidevineCdmBaseDirectory().AppendASCII(current_version_.GetString())
+          .AppendASCII(kWidevineCdmFileName);
+
+  // Ideally we should check if PathExists(installed_cdm_path) here. But this

[Sorin Jianu, 2013/06/21 19:49:24]

This comment can be removed. The function just maps file names to their
location, no need to do any I/O to check the file presence or their integrity. 

You could also avoid the named local variable here and just assigned to the out
parameter of the function. If you prefer the named variable, you could declare
it const. 

Please read waffle's comment about what is expected of this function.

[xhwang, 2013/06/21 19:56:04]

Done.

+  // thread does not allow IO.
+
+  *installed_file = installed_cdm_path;
+  return true;
 }
 
 void FinishWidevineCdmUpdateRegistration(ComponentUpdateService* cus,