Restrict WEBM Key ID data to 128-bits for Android

content/browser/media/cdm/browser_cdm_manager.cc

Index: content/browser/media/cdm/browser_cdm_manager.cc
diff --git a/content/browser/media/cdm/browser_cdm_manager.cc b/content/browser/media/cdm/browser_cdm_manager.cc
index 0bd8a78e68d3a8c6a1d57b9104e7afa973426cd7..e3c2d61d4d36792fa9c44127496b9a8f8cef6d1f 100644
--- a/content/browser/media/cdm/browser_cdm_manager.cc
+++ b/content/browser/media/cdm/browser_cdm_manager.cc
@@ -36,6 +36,11 @@ using media::MediaKeys;
 
 namespace {
 
+#if defined(OS_ANDROID)
+// Android only supports 128-bit key IDs.
+const size_t kAndroidKeyIdBytes = 128 / 8;
+#endif
+
 // The ID used in this class is a concatenation of |render_frame_id| and
 // |cdm_id|, i.e. (render_frame_id << 32) + cdm_id.
 
@@ -345,6 +350,15 @@ void BrowserCdmManager::OnCreateSessionAndGenerateRequest(
     promise->reject(MediaKeys::INVALID_ACCESS_ERROR, 0, "Init data too long.");
     return;
   }
+#if defined(OS_ANDROID)
+  // On Android 'webm' initData should contain exactly 1 key.

[ddorwin, 2015/05/15 16:54:35]

Remove "On Android ". This is always true for WebM.

Even better, something like:
'webm' initData is a single key ID. On Android the length is restricted.

[jrummell, 2015/05/15 17:52:21]

Done.

+  if (init_data_type == INIT_DATA_TYPE_WEBM &&
+      init_data.size() != kAndroidKeyIdBytes) {
+    promise->reject(MediaKeys::INVALID_ACCESS_ERROR, 0,
+                    "'webm' initData does not contain a single key.");

[ddorwin, 2015/05/15 16:54:35]

By definition, it is a single key ID. The problem is the length.

[jrummell, 2015/05/15 17:52:21]

Done.

+    return;
+  }
+#endif
 
   media::EmeInitDataType eme_init_data_type;
   switch (init_data_type) {