Implement WebStorage API methods

base/android/jni_array.cc

Index: base/android/jni_array.cc
diff --git a/base/android/jni_array.cc b/base/android/jni_array.cc
index fe2aadb745c087386bf01512108a2c6235c1d3d8..8236e5da312eaec1a3cb904e7668e69d0c78e48f 100644
--- a/base/android/jni_array.cc
+++ b/base/android/jni_array.cc
@@ -25,6 +25,20 @@ ScopedJavaLocalRef<jbyteArray> ToJavaByteArray(
   return ScopedJavaLocalRef<jbyteArray>(env, byte_array);
 }
 
+ScopedJavaLocalRef<jlongArray> ToJavaLongArray(
+    JNIEnv* env, const int64* longs, size_t len) {

[mkosiba (inactive), 2013/02/20 12:21:38]

I know the function above uses a raw C-style array but std::vector is just as
efficient, guaranteed to take up a continuous block of memory (so memcpy-ing it
is OK) and you don't risk mis-specifying the len.

Also, it seems all ToJavaLongArray callsites use a vector. You probably should
add a wrapper that takes in a vector and calls this method to do the actual
work.

[boliu, 2013/02/20 20:14:16]

Overloaded the method with a vector version and updated the test to reflect
that.

+  jlongArray long_array = env->NewLongArray(len);
+  CheckException(env);
+  DCHECK(long_array);
+
+  jlong* elements = env->GetLongArrayElements(long_array, NULL);
+  memcpy(elements, longs, len * sizeof(*longs));

[mkosiba (inactive), 2013/02/20 12:21:38]

I can't remember what the exact issue was but one of the C++ books I read
recommended using the type (int64) rather than the variable in this case. 

I'd say that it's OK to hardcode the type since the method does explicitly deal
with longs (aka int64s) so the chances that you change the type of *longs and
forget to update the code are low.

[boliu, 2013/02/20 20:14:16]

I remember in one of the effective c++ books, the recommendation is the exact
opposite, because then the sizeof and the type of the variable will not get out
of sync.
I don't really care much either way and I see sizeof with both styles under
base/. So...I'll do whatever joth says? If he doesn't care, I'll use the type.

+  env->ReleaseLongArrayElements(long_array, elements, 0);
+  CheckException(env);
+
+  return ScopedJavaLocalRef<jlongArray>(env, long_array);
+}
+
 ScopedJavaLocalRef<jobjectArray> ToJavaArrayOfByteArray(
     JNIEnv* env, const std::vector<std::string>& v) {
   ScopedJavaLocalRef<jclass> byte_array_clazz = GetClass(env, "[B");