Fix error prone warnings

Since we switched to error prone to do static analysis, fixing warnings
introduced by my changes.

Bug: None
Change-Id: I9b4e2593f217b424658e344957f8f4aadff2d2cd
Reviewed-on: https://chromium-review.googlesource.com/777947Reviewed-by: Bo <boliu@chromium.org>
Commit-Queue: Shimi Zhang <ctzsm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517882}

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

@@ -108,10 +108,12 @@ public class SelectionIndicesConverter {
         }
 
         if (end <= initialStartOffset) {
-            wordIndices[1] = -countWordsForward(end, initialStartOffset, breakIterator);
+            wordIndices[1] =
+                    -countWordsForward(/* start = */ end, initialStartOffset, breakIterator);
         } else {
             // end > initialStartOffset
-            wordIndices[1] = countWordsBackward(end, initialStartOffset, breakIterator);
+            wordIndices[1] =
+                    countWordsBackward(/* start = */ end, initialStartOffset, breakIterator);
         }
 
         return true;

content/public/android/junit/src/org/chromium/content/browser/SelectionPopupControllerTest.java

@@ -55,7 +55,7 @@ public class SelectionPopupControllerTest {
     private static final String AMPHITHEATRE_FULL = "1600 Amphitheatre Parkway";
     private static final String AMPHITHEATRE = "Amphitheatre";
 
-    private class TestSelectionClient implements SelectionClient {
+    private static class TestSelectionClient implements SelectionClient {
         private SelectionClient.Result mResult;
         private SelectionClient.ResultCallback mResultCallback;
 
@@ -94,7 +94,7 @@ public class SelectionPopupControllerTest {
         }
     }
 
-    class SelectionClientOnlyReturnTrue extends TestSelectionClient {
+    private static class SelectionClientOnlyReturnTrue extends TestSelectionClient {
         @Override
         public boolean requestSelectionPopupUpdates(boolean shouldSuggest) {
             return true;