Fix getUserMedia may get low FPS when the selected FPS is out of rang…

…e of the camera FPS eg 31 fps is wanted, the supported range is [11,30] then the final FPS should be selected to be 30 instead of 11

Review URL: https://codereview.chromium.org/641293002

Cr-Commit-Position: refs/heads/master@{#301661}

AUTHORS

@@ -219,6 +219,7 @@ Joel Stanley <joel@jms.id.au>
 Johannes Rudolph <johannes.rudolph@googlemail.com>
 John Yani <vanuan@gmail.com>
 John Yoo <nearbyh13@gmail.com>
+Johnson Lin <johnson.lin@intel.com>
 Jonathan Frazer <listedegarde@gmail.com>
 Jonathan Hacker <jhacker@arcanefour.com>
 Jongsoo Lee <leejongsoo@gmail.com>

media/base/android/java/src/org/chromium/media/VideoCaptureCamera.java

@@ -110,12 +110,15 @@ public boolean allocate(int width, int height, int frameRate) {
             Log.e(TAG, "allocate: no fps range found");
             return false;
         }
+        // API fps ranges are scaled up x1000 to avoid floating point.
+        int frameRateScaled = frameRate * 1000;
         // Use the first range as the default chosen range.
         int[] chosenFpsRange = listFpsRange.get(0);
-        int chosenFrameRate = (chosenFpsRange[0] + 999) / 1000;
+        int frameRateNearest = Math.abs(frameRateScaled - chosenFpsRange[0]) <
+                               Math.abs(frameRateScaled - chosenFpsRange[1]) ?
+                               chosenFpsRange[0] : chosenFpsRange[1];
+        int chosenFrameRate = (frameRateNearest + 999) / 1000;
         int fpsRangeSize = Integer.MAX_VALUE;
-        // API fps ranges are scaled up x1000 to avoid floating point.
-        int frameRateScaled = frameRate * 1000;
         for (int[] fpsRange : listFpsRange) {
             if (fpsRange[0] <= frameRateScaled && frameRateScaled <= fpsRange[1]
                     && (fpsRange[1] - fpsRange[0]) <= fpsRangeSize) {