Set the javac target and source to 1.7

BUG=336589
TBR=yfriedman@chromium.org

Review URL: https://codereview.chromium.org/545363002

Cr-Commit-Position: refs/heads/master@{#295162}

base/android/java/src/org/chromium/base/CollectionUtil.java

@@ -17,12 +17,14 @@ import java.util.HashSet;
 public final class CollectionUtil {
     private CollectionUtil() {}
 
+    @SafeVarargs
     public static <E> HashSet<E> newHashSet(E... elements) {
         HashSet<E> set = new HashSet<E>(elements.length);
         Collections.addAll(set, elements);
         return set;
     }
 
+    @SafeVarargs
     public static <E> ArrayList<E> newArrayList(E... elements) {
         ArrayList<E> list = new ArrayList<E>(elements.length);
         Collections.addAll(list, elements);

build/android/gyp/javac.py

@@ -78,8 +78,8 @@ def DoJavac(
 
   javac_args = [
       '-g',
-      '-source', '1.5',
-      '-target', '1.5',
+      '-source', '1.7',
+      '-target', '1.7',
       '-classpath', ':'.join(classpath),
       '-d', classes_dir]
   if chromium_code: