Replace kMediaDrmEnableNonCompositing swicth with use_video_overlay_for_embedded_encrypted_video pref

Disables kMediaDrmEnableNonCompositing by default in WebView.
It is now controlled by the pref.

Also updates comments related to enabling unprefixed EME.

BUG=470275,470279

Review URL: https://codereview.chromium.org/1045173002

Cr-Commit-Position: refs/heads/master@{#323420}

2 files changed, 13 insertions, 7 deletions

diff --git a/components/cdm/renderer/android_key_systems.cc b/components/cdm/renderer/android_key_systems.cc
index d9bb106..e1538ba 100644
--- a/components/cdm/renderer/android_key_systems.cc
+++ b/components/cdm/renderer/android_key_systems.cc
@@ -39,21 +39,22 @@ static SupportedKeySystemResponse QueryKeySystemSupport(
   return response;
 }
 
-void AddAndroidWidevine(std::vector<KeySystemInfo>* concrete_key_systems) {
+void AddAndroidWidevine(std::vector<KeySystemInfo>* concrete_key_systems,
+                        bool is_non_compositing_supported) {
   SupportedKeySystemResponse response = QueryKeySystemSupport(
       kWidevineKeySystem);
 
   // When creating the WIDEVINE key system, BrowserCdmFactoryAndroid configures
-  // the CDM's security level based on the --mediadrm-enable-non-compositing
-  // flag (L1 if the flag is enabled, L3 otherwise). Therefore the supported
-  // codec/robustenss combinations depend on that flag.
+  // the CDM's security level based on a pref. Therefore the supported
+  // codec/robustenss combinations depend on that pref, represented by
+  // |bool is_non_compositing_supported|.
   // TODO(sandersd): For unprefixed, set the security level based on the
   // requested robustness instead of the flag. http://crbug.com/467779
+  // We should also stop using the term "non_compositing."
   SupportedCodecs codecs = response.compositing_codecs;
   EmeRobustness max_audio_robustness = EmeRobustness::SW_SECURE_CRYPTO;
   EmeRobustness max_video_robustness = EmeRobustness::SW_SECURE_CRYPTO;
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kMediaDrmEnableNonCompositing)) {
+  if (is_non_compositing_supported) {
     codecs = response.non_compositing_codecs;
     max_audio_robustness = EmeRobustness::HW_SECURE_CRYPTO;
     max_video_robustness = EmeRobustness::HW_SECURE_ALL;
diff --git a/components/cdm/renderer/android_key_systems.h b/components/cdm/renderer/android_key_systems.h
index fb962b1..b27f57c 100644
--- a/components/cdm/renderer/android_key_systems.h
+++ b/components/cdm/renderer/android_key_systems.h
@@ -12,7 +12,12 @@
 namespace cdm {
 
 void AddAndroidWidevine(
-    std::vector<media::KeySystemInfo>* concrete_key_systems);
+    std::vector<media::KeySystemInfo>* concrete_key_systems,
+    // TODO(sandersd): Non-compositing support depends on the
+    // use_video_overlay_for_embedded_encrypted_video pref, which may differ per
+    // WebContents, meaning this cannot be a global setting for the renderer
+    // process. Handle this per WebContents instead. http://crbug.com/467779
+    bool is_non_compositing_supported);
 
 // Add platform-supported key systems which are not explicitly handled
 // by Chrome.