Add support for Flash Player Component updates on Linux

This change adds support for Flash Player Component updates on Linux.
It enables the component updater on Linux, and creates a hints file that
the zygote will use to locate and preload the latest component updated flash.

This should not affect component update OS X and Windows, however, because
it forks the update path on Linux from those platforms, there is a risk of a bug
that could affect component update on OS X and Windows.

BUG=460595

Review URL: https://codereview.chromium.org/1261333004

Cr-Commit-Position: refs/heads/master@{#343435}

1 files changed, 13 insertions, 0 deletions

diff --git a/chrome/common/chrome_paths.cc b/chrome/common/chrome_paths.cc
index 74bf041..0da194d 100644
--- a/chrome/common/chrome_paths.cc
+++ b/chrome/common/chrome_paths.cc
@@ -60,6 +60,11 @@ const base::FilePath::CharType kFilepathSinglePrefExtensions[] =
 #else
     FILE_PATH_LITERAL("/usr/share/chromium/extensions");
 #endif  // defined(GOOGLE_CHROME_BUILD)
+
+// The path to the hint file that tells the pepper plugin loader
+// where it can find the latest component updated flash.
+const base::FilePath::CharType kComponentUpdatedFlashHint[] =
+    FILE_PATH_LITERAL("latest-component-updated-flash");
 #endif  // defined(OS_LINUX)
 
 static base::LazyInstance<base::FilePath>
@@ -566,6 +571,14 @@ bool PathProvider(int key, base::FilePath* result) {
       cur = cur.Append(kOfflinePageMetadataDirname);
       break;
 #endif  // defined(OS_ANDROID)
+#if defined(OS_LINUX)
+    case chrome::FILE_COMPONENT_FLASH_HINT:
+      if (!PathService::Get(chrome::DIR_COMPONENT_UPDATED_PEPPER_FLASH_PLUGIN,
+                            &cur))
+        return false;
+      cur = cur.Append(kComponentUpdatedFlashHint);
+      break;
+#endif  // defined(OS_LINUX)
 
     default:
       return false;