Fix Java Checkstyle issues.

content/public/android/java/src/org/chromium/content/browser/DeviceSensors.java

Index: content/public/android/java/src/org/chromium/content/browser/DeviceSensors.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/DeviceSensors.java b/content/public/android/java/src/org/chromium/content/browser/DeviceSensors.java
index 76e77f4fef05590f73291705e359cd58f3b79b41..c78b52189bed735e10ac3318385c00ab47c5bae5 100644
--- a/content/public/android/java/src/org/chromium/content/browser/DeviceSensors.java
+++ b/content/public/android/java/src/org/chromium/content/browser/DeviceSensors.java
@@ -271,7 +271,7 @@ class DeviceSensors implements SensorEventListener {
      * </ul>
      * <p>
      *
-     * @param R
+     * @param r

[riju_, 2014/10/14 06:25:58]

Please check with Tim for this change. 
Have a look at crrev.com/591383002 

[timvolodine, 2014/10/14 13:12:57]

The use of R was to make code consistent with Android, e.g. see
SensorManager.java getRotationMatrix and others where a capital letter is used
to denote a matrix. IMHO making it "r" is confusing and somewhat breaks the
existing comments.

[aurimas (slooooooooow), 2014/10/14 14:48:17]

According to the style guide the method parameter names have to be
lowerCamelCase.
https://google-styleguide.googlecode.com/svn/trunk/javaguide.html#s5.2.6-para...

Should I rename it to R to matrix? Or do you have better suggestions? I can
update all the comments for this method too.

[timvolodine, 2014/10/14 16:29:40]

I would argue for an exception for math functions ;), but if you want to get rid
of one-char parameter name then "matrix" sounds like a reasonable alternative.

[aurimas (slooooooooow), 2014/10/14 16:38:00]

I agree that it is kind of silly, but this is the only case with an upper case
method parameter name in entire code base and it would suck if we could not
enable this style check just because of it :/

      *        a 3x3 rotation matrix {@see SensorManager.getRotationMatrix}.
      *
      * @param values
@@ -280,7 +280,7 @@ class DeviceSensors implements SensorEventListener {
      * @return the array values passed as argument.
      */
     @VisibleForTesting
-    public static double[] computeDeviceOrientationFromRotationMatrix(float[] R, double[] values) {
+    public static double[] computeDeviceOrientationFromRotationMatrix(float[] r, double[] values) {
         /*
          * 3x3 (length=9) case:
          *   /  R[ 0]   R[ 1]   R[ 2]  \
@@ -288,39 +288,39 @@ class DeviceSensors implements SensorEventListener {
          *   \  R[ 6]   R[ 7]   R[ 8]  /
          *
          */
-        if (R.length != 9)
-            return values;
-
-        if (R[8] > 0) {  // cos(beta) > 0
-            values[0] = Math.atan2(-R[1], R[4]);
-            values[1] = Math.asin(R[7]);           // beta (-pi/2, pi/2)
-            values[2] = Math.atan2(-R[6], R[8]);   // gamma (-pi/2, pi/2)
-        } else if (R[8] < 0) {  // cos(beta) < 0
-            values[0] = Math.atan2(R[1], -R[4]);
-            values[1] = -Math.asin(R[7]);
+        if (r.length != 9) return values;
+
+        if (r[8] > 0) {  // cos(beta) > 0
+            values[0] = Math.atan2(-r[1], r[4]);
+            values[1] = Math.asin(r[7]);           // beta (-pi/2, pi/2)
+            values[2] = Math.atan2(-r[6], r[8]);   // gamma (-pi/2, pi/2)
+        } else if (r[8] < 0) {  // cos(beta) < 0
+            values[0] = Math.atan2(r[1], -r[4]);
+            values[1] = -Math.asin(r[7]);
             values[1] += (values[1] >= 0) ? -Math.PI : Math.PI; // beta [-pi,-pi/2) U (pi/2,pi)
-            values[2] = Math.atan2(R[6], -R[8]);   // gamma (-pi/2, pi/2)
+            values[2] = Math.atan2(r[6], -r[8]);   // gamma (-pi/2, pi/2)
         } else { // R[8] == 0
-            if (R[6] > 0) {  // cos(gamma) == 0, cos(beta) > 0
-                values[0] = Math.atan2(-R[1], R[4]);
-                values[1] = Math.asin(R[7]);       // beta [-pi/2, pi/2]
+            if (r[6] > 0) {  // cos(gamma) == 0, cos(beta) > 0
+                values[0] = Math.atan2(-r[1], r[4]);
+                values[1] = Math.asin(r[7]);       // beta [-pi/2, pi/2]
                 values[2] = -Math.PI / 2;          // gamma = -pi/2
-            } else if (R[6] < 0) { // cos(gamma) == 0, cos(beta) < 0
-                values[0] = Math.atan2(R[1], -R[4]);
-                values[1] = -Math.asin(R[7]);
+            } else if (r[6] < 0) { // cos(gamma) == 0, cos(beta) < 0
+                values[0] = Math.atan2(r[1], -r[4]);
+                values[1] = -Math.asin(r[7]);
                 values[1] += (values[1] >= 0) ? -Math.PI : Math.PI; // beta [-pi,-pi/2) U (pi/2,pi)
                 values[2] = -Math.PI / 2;          // gamma = -pi/2
             } else { // R[6] == 0, cos(beta) == 0
                 // gimbal lock discontinuity
-                values[0] = Math.atan2(R[3], R[0]);
-                values[1] = (R[7] > 0) ? Math.PI / 2 : -Math.PI / 2;  // beta = +-pi/2
+                values[0] = Math.atan2(r[3], r[0]);
+                values[1] = (r[7] > 0) ? Math.PI / 2 : -Math.PI / 2;  // beta = +-pi/2
                 values[2] = 0;                                        // gamma = 0
             }
         }
 
         // alpha is in [-pi, pi], make sure it is in [0, 2*pi).
-        if (values[0] < 0)
+        if (values[0] < 0) {
             values[0] += 2 * Math.PI; // alpha [0, 2*pi)
+        }
 
         return values;
     }