Log Android WebAudio buffer sizes

Log the recommended audio HW buffer size as well as the actual buffer
size.

These were removed at some point and we're putting them back because
it's relatively hard to get this information.  These are always
printed, but only once when an AudioContext is created, so we aren't
actually spamming the console logs.

NOPRESUBMIT=true

Bug: 783929
Test: 
Change-Id: I6cea5dca504292cae9160899e8240f384453f913
Reviewed-on: https://chromium-review.googlesource.com/764541
Commit-Queue: Raymond Toy <rtoy@chromium.org>
Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Reviewed-by: Olga Sharonova <olka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#516008}

media/base/audio_latency.cc

@@ -142,8 +142,13 @@ int AudioLatency::GetInteractiveBufferSize(int hardware_buffer_size) {
   // the jitter.
   const int kSmallBufferSize = 1024;
   const int kDefaultCallbackBufferSize = 2048;
+
+  LOG(INFO) << "audioHardwareBufferSize = " << hardware_buffer_size;
+
   if (hardware_buffer_size <= kSmallBufferSize)
-    return kDefaultCallbackBufferSize;
+    hardware_buffer_size = kDefaultCallbackBufferSize;
+
+  LOG(INFO) << "callbackBufferSize      = " << hardware_buffer_size;
 #endif
 
   return hardware_buffer_size;