Android: Change camera fps range selection

This CL changes the logic in
CameraEnumerationAndroid.getClosestSupportedFramerateRange() to prefer
fps ranges with a low lower bound so the camera can adjust for
brightness conditions.

To test the functionality of the fps range selection, JUnit tests are
added. This required a new target in api_tests.gyp. JUnit tests are
preferable over instrumentation tests
(libjingle_peerconnection_android_unittest) because they are faster and
simpler.

R=kjellander@webrtc.org, sakal@webrtc.org

Review URL: https://codereview.webrtc.org/2013413002 .

Cr-Commit-Position: refs/heads/master@{#12964}

webrtc/androidjunit/OWNERS

@@ -0,0 +1,2 @@
+magjed@webrtc.org
+sakal@webrtc.org

webrtc/androidjunit/src/org/webrtc/CameraEnumerationTest.java

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+/*
+ *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+package org.webrtc;
+
+import static org.junit.Assert.assertEquals;
+import static org.webrtc.CameraEnumerationAndroid.getClosestSupportedFramerateRange;
+
+import org.webrtc.CameraEnumerationAndroid.CaptureFormat;
+import org.webrtc.CameraEnumerationAndroid.CaptureFormat.FramerateRange;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+
+import java.util.Arrays;
+
+/**
+ * Tests for CameraEnumerationAndroid.
+ */
+@RunWith(RobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class CameraEnumerationTest {
+  @Test
+  public void testGetClosestSupportedFramerateRange() {
+    assertEquals(new FramerateRange(10000, 30000),
+        getClosestSupportedFramerateRange(
+            Arrays.asList(new FramerateRange(10000, 30000),
+                          new FramerateRange(30000, 30000)),
+            30 /* requestedFps */));
+
+    assertEquals(new FramerateRange(10000, 20000),
+        getClosestSupportedFramerateRange(
+            Arrays.asList(new FramerateRange(0, 30000),
+                          new FramerateRange(10000, 20000),
+                          new FramerateRange(14000, 16000),
+                          new FramerateRange(15000, 15000)),
+            15 /* requestedFps */));
+
+    assertEquals(new FramerateRange(10000, 20000),
+        getClosestSupportedFramerateRange(
+            Arrays.asList(new FramerateRange(15000, 15000),
+                          new FramerateRange(10000, 20000),
+                          new FramerateRange(10000, 30000)),
+            10 /* requestedFps */));
+  }
+}