Generalize the API of WakeLockContext mojo interface.

device/wake_lock/public/interfaces/wake_lock_context.mojom

Index: device/wake_lock/public/interfaces/wake_lock_context.mojom
diff --git a/device/wake_lock/public/interfaces/wake_lock_context.mojom b/device/wake_lock/public/interfaces/wake_lock_context.mojom
index bb01e64b8bfd1839eac0726b374020babdce49e8..178994b46cfc87bf7c3d64254fdc63fff04d39dc 100644
--- a/device/wake_lock/public/interfaces/wake_lock_context.mojom
+++ b/device/wake_lock/public/interfaces/wake_lock_context.mojom
@@ -6,8 +6,34 @@ module device.mojom;
 
 import "device/wake_lock/public/interfaces/wake_lock_service.mojom";
 
+// TODO(heke): Switch PowerSaveBlocker to use WakeLockType and WakeLockReason

[blundell, 2017/05/09 15:53:24]

I think that we could just do the mapping from mojom type to PowerSaveBlocker
type in wake_lock_service_impl.cc with this TODO there, and incrementally
convert clients of PowerSaveBlocker to pass the mojom types as we convert them
to be clients of WakeLock. That way once there are no more clients of
PowerSaveBlocker we can just convert PowerSaveBlocker itself to use the mojom
types and eliminate the mapping from wake_lock_service_impl.cc: We don't then
need to go back and convert all clients in a second pass. WDYT?

[ke.he, 2017/05/10 07:00:20]

Good idea, in this way we don't need the typemap either. I'll let the
MediaWebContentsObsever pass the mojom types first.

Done.

+// below once it has no direct consumers.
+enum WakeLockType {
+    // Prevent the application from being suspended. On some platforms, apps may
+    // be suspended when they are not visible to the user. This type of block
+    // requests that the app continue to run in that case, and on all platforms
+    // prevents the system from sleeping.
+    // Example use cases: downloading a file, playing audio.
+    PreventAppSuspension = 0,
+
+    // Prevent the display from going to sleep. This also has the side effect of
+    // preventing the system from sleeping, but does not necessarily prevent the
+    // app from being suspended on some platforms if the user hides it.
+    // Example use case: playing video.
+    PreventDisplaySleep = 1,
+};
+
+enum WakeLockReason {
+    // Audio is being played.
+    ReasonAudioPlayback = 0,
+    // Video is being played.
+    ReasonVideoPlayback = 1,
+    // WakeLock for some other reason.
+    ReasonOther = 2,
+};
+
 // Context in which WakeLockService instances operate.
 interface WakeLockContext {
   // Gets a WakeLockService within this context.
-  GetWakeLock(WakeLockService& wake_lock);
+  GetWakeLock(WakeLockType type, WakeLockReason reason, string description, WakeLockService& wake_lock);
 };