Bug 1278574 - [1.3] Allow only a single media decoder (pair) on Android 4.2 and earlier. r=jya,snorp

dom/media/MediaDecoderReader.cpp

@@ -16,7 +16,6 @@
 #include "mozilla/Mutex.h"
 #include <stdint.h>
 #include <algorithm>
-#include <list>
 
 using namespace mozilla::media;
 

dom/media/MediaPrefs.h

@@ -6,6 +6,10 @@
 #ifndef MEDIA_PREFS_H
 #define MEDIA_PREFS_H
 
+#ifdef MOZ_WIDGET_ANDROID
+#include "AndroidBridge.h"
+#endif
+
 // First time MediaPrefs::GetSingleton() needs to be called on the main thread,
 // before any of the methods accessing the values are used, but after
 // the Preferences system has been initialized.
@@ -121,7 +125,7 @@ private:
   DECL_MEDIA_PREF("media.webspeech.recognition.force_enable", WebSpeechRecognitionForceEnabled, bool, false);
 
   DECL_MEDIA_PREF("media.num-decode-threads",                 MediaThreadPoolDefaultCount, uint32_t, 4);
-  DECL_MEDIA_PREF("media.decoder.limit",                      MediaDecoderLimit, uint32_t, -1);
+  DECL_MEDIA_PREF("media.decoder.limit",                      MediaDecoderLimit, int32_t, MediaDecoderLimitDefault());
 
 public:
   // Manage the singleton:
@@ -132,6 +136,21 @@ private:
   template<class T> friend class StaticAutoPtr;
   static StaticAutoPtr<MediaPrefs> sInstance;
 
+  // Default value functions
+  static int32_t MediaDecoderLimitDefault()
+  {
+#ifdef MOZ_WIDGET_ANDROID
+    if (AndroidBridge::Bridge() &&
+        AndroidBridge::Bridge()->GetAPIVersion() < 18) {
+      // Older Android versions have broken support for multiple simultaneous
+      // decoders, see bug 1278574.
+      return 1;
+    }
+#endif
+    // Otherwise, set no decoder limit.
+    return -1;
+  }
+
   // Creating these to avoid having to include Preferences.h in the .h
   static void PrefAddVarCache(bool*, const char*, bool);
   static void PrefAddVarCache(int32_t*, const char*, int32_t);

layout/build/nsLayoutStatics.cpp

@@ -309,7 +309,6 @@ nsLayoutStatics::Initialize()
 #endif
 
   MediaDecoder::InitStatics();
-  MediaPrefs::GetSingleton();
 
   PromiseDebugging::Init();