Add UMA stats for the resolution camera is started in.

webrtc/api/android/java/src/org/webrtc/CameraEnumerationAndroid.java

Index: webrtc/api/android/java/src/org/webrtc/CameraEnumerationAndroid.java
diff --git a/webrtc/api/android/java/src/org/webrtc/CameraEnumerationAndroid.java b/webrtc/api/android/java/src/org/webrtc/CameraEnumerationAndroid.java
index 48ee1a373170fc945b403bd8d07b0918a1c356ce..c5cdcf7d56efd62a5d2ffe5d43dc7e24620d488b 100644
--- a/webrtc/api/android/java/src/org/webrtc/CameraEnumerationAndroid.java
+++ b/webrtc/api/android/java/src/org/webrtc/CameraEnumerationAndroid.java
@@ -13,14 +13,41 @@ package org.webrtc;
 import static java.lang.Math.abs;
 
 import android.graphics.ImageFormat;
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
+import org.webrtc.Metrics.Histogram;
 
 @SuppressWarnings("deprecation")
 public class CameraEnumerationAndroid {
   private final static String TAG = "CameraEnumerationAndroid";
 
+  static final ArrayList<Size> COMMON_RESOLUTIONS = new ArrayList<Size>(Arrays.asList(
+      // 0, Unknown resolution
+      new Size(160, 120), // 1, QQVGA
+      new Size(240, 160), // 2, HQVGA
+      new Size(320, 240), // 3, QVGA
+      new Size(400, 240), // 4, WQVGA
+      new Size(480, 320), // 5, HVGA
+      new Size(640, 360), // 6, nHD
+      new Size(640, 480), // 7, VGA
+      new Size(768, 480), // 8, WVGA
+      new Size(854, 480), // 9, FWVGA
+      new Size(800, 600), // 10, SVGA
+      new Size(960, 540), // 11, qHD
+      new Size(960, 640), // 12, DVGA
+      new Size(1024, 576), // 13, WSVGA
+      new Size(1024, 600), // 14, WVSGA
+      new Size(1280, 720), // 15, HD
+      new Size(1280, 1024), // 16, SXGA
+      new Size(1920, 1080), // 17, Full HD
+      new Size(1920, 1440), // 18, Full HD 4:3
+      new Size(2560, 1440), // 19, QHD
+      new Size(3840, 2160) // 20, UHD
+      ));
+
   public static class CaptureFormat {
     // Class to represent a framerate range. The framerate varies because of lightning conditions.
     // The values are multiplied by 1000, so 1000 represents one frame per second.
@@ -169,4 +196,12 @@ public class CameraEnumerationAndroid {
       }
     });
   }
+
+  // Helper method for camera classes.
+  static void reportCameraResolution(Histogram histogram, Size resolution) {
+    int index = COMMON_RESOLUTIONS.indexOf(resolution);
+    // 0 is reserved for unknown resolution, so add 1.
+    // indexOf returns -1 for unknown resolutions so it becomes 0 automatically.
+    histogram.addSample(index + 1);
+  }
 }