Check whether the Pepper CDM is available before adding the key system.

chrome/renderer/media/chrome_key_systems.cc

Index: chrome/renderer/media/chrome_key_systems.cc
diff --git a/chrome/renderer/media/chrome_key_systems.cc b/chrome/renderer/media/chrome_key_systems.cc
index 634e83dc06a168a361659e4d4a5d410fe4d524e4..8066299221d3e66579b5ac2ddc704b1c3e8eb900 100644
--- a/chrome/renderer/media/chrome_key_systems.cc
+++ b/chrome/renderer/media/chrome_key_systems.cc
@@ -5,6 +5,8 @@
 #include "chrome/renderer/media/chrome_key_systems.h"
 
 #include "base/logging.h"
+#include "chrome/common/render_messages.h"
+#include "content/public/renderer/render_thread.h"
 
 #include "widevine_cdm_version.h" // In SHARED_INTERMEDIATE_DIR.
 
@@ -51,13 +53,6 @@ static void AddWidevineForCodecs(
       0xA3, 0xC8, 0x27, 0xDC, 0xD5, 0x1D, 0x21, 0xED };
 #endif
 
-#if defined(WIDEVINE_CDM_MIN_GLIBC_VERSION)
-  Version glibc_version(gnu_get_libc_version());
-  DCHECK(glibc_version.IsValid());
-  if (glibc_version.IsOlderThan(WIDEVINE_CDM_MIN_GLIBC_VERSION))
-    return;
-#endif  // defined(WIDEVINE_CDM_MIN_GLIBC_VERSION)
-
   KeySystemInfo info(kWidevineKeySystem);
 
   if (supported_codecs & WEBM_VP8_AND_VORBIS) {
@@ -87,9 +82,30 @@ static void AddWidevineForCodecs(
 }
 
 #if defined(ENABLE_PEPPER_CDMS)
+static bool IsPepperCdmAvailable(const std::string& pepper_type) {
+  bool is_available = false;

[scherkus (not reviewing), 2013/09/11 22:34:41]

do you want cache this value?

[ddorwin, 2013/09/16 17:17:58]

It's not really necessary. This should only happen once per renderer process
since it is invoked by KeySystems, which is a lazily-instantiated singleton.
That's a bit of implementation knowledge that this code probably shouldn't have,
but adding static values just adds complexity for no real gain. Note that this
is not called for every canPlayType() call since this code is run to _add_ key
systems. WDYT?

P.S. If we were going to cache this value, it would probably need to be at line
104.

[scherkus (not reviewing), 2013/09/16 17:42:05]

seems fine as is

+  content::RenderThread::Get()->Send(
+      new ChromeViewHostMsg_IsSupportingPluginAvailable(pepper_type,
+                                                        &is_available));
+
+  return is_available;
+}
+
 // Supported types are determined at compile time.
 static void AddPepperBasedWidevine(
     std::vector<KeySystemInfo>* concrete_key_systems) {
+#if defined(WIDEVINE_CDM_MIN_GLIBC_VERSION)
+  Version glibc_version(gnu_get_libc_version());
+  DCHECK(glibc_version.IsValid());
+  if (glibc_version.IsOlderThan(WIDEVINE_CDM_MIN_GLIBC_VERSION))
+    return;
+#endif  // defined(WIDEVINE_CDM_MIN_GLIBC_VERSION)
+
+  if (!IsPepperCdmAvailable(kWidevineCdmPluginMimeType)) {
+    DVLOG(1) << "Widevine CDM is not currently available.";
+    return;
+  }
+
   SupportedCodecs supported_codecs = WEBM_VP8_AND_VORBIS;
 
 #if defined(USE_PROPRIETARY_CODECS)