Enabling autoplay and fullscreen for downloaded media

chrome/browser/android/tab_android.cc

Index: chrome/browser/android/tab_android.cc
diff --git a/chrome/browser/android/tab_android.cc b/chrome/browser/android/tab_android.cc
index 421ec3dfe30464342678a851c699dc5254197e65..e97c04f6a310f82fe757283559ae4e11b6600374 100644
--- a/chrome/browser/android/tab_android.cc
+++ b/chrome/browser/android/tab_android.cc
@@ -73,6 +73,7 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/browser_controls_state.h"
 #include "content/public/common/resource_request_body.h"
+#include "content/public/common/web_preferences.h"
 #include "jni/Tab_jni.h"
 #include "net/base/escape.h"
 #include "skia/ext/image_operations.h"
@@ -716,6 +717,19 @@ bool TabAndroid::HasPrerenderedUrl(JNIEnv* env,
   return HasPrerenderedUrl(gurl);
 }
 
+void TabAndroid::ConfigureEmbeddedMediaExperience(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj) {
+  content::RenderViewHost* host = web_contents()->GetRenderViewHost();
+  if (!host)
+    return;
+
+  content::WebPreferences prefs = host->GetWebkitPreferences();
+  prefs.user_gesture_required_for_media_playback = false;

[mlamouri (slow - plz ping), 2017/02/17 10:01:43]

Is it needed? Can't you simply autoplay from C++ to avoid worrying about this?

[shaktisahu, 2017/02/17 19:18:06]

Done. Thanks!

+  prefs.embedded_media_experience_enabled = true;
+  host->UpdateWebkitPreferences(prefs);

[mlamouri (slow - plz ping), 2017/02/17 10:01:43]

That does not sound correct because if any one calls UpdateWebkitPreferences
later, your settings will be disabled. Instead, you should make sure that when
the settings are refreshed, it checks for the Tab's information.

[shaktisahu, 2017/02/17 19:18:06]

I looked around and didn't find any function that does it differently.
Whoever wants to set prefs, they first call GetWebkitPreferences to get the
existing prefs and add their preferences to it. So, unless someone wants to
specifically update embedded_media_experience_enabled, it should't be an issue.

[mlamouri (slow - plz ping), 2017/02/20 11:31:50]

The issue is that you are calling UpdateWebkitPreferences with the value set to
true but any one calling this later will revert your setting. The expectation is
that UpdateWebkitPreferences will have the logic that checks for the value. You
can look at |media_playback_gesture_whitelist_scope| for an example.

[shaktisahu, 2017/02/21 07:02:56]

Done.
Thanks! I think this is especially useful for the situation where the current
RenderViewHost or even WebContents is swapped for a new one, and we still get
our preference set correctly.

+}
+
 namespace {
 
 class ChromeInterceptNavigationDelegate : public InterceptNavigationDelegate {