Do not cache POST response as Cache is indexed with url.

mRequestHandle is only set from Network. So we can skip checking whether url is Network url if mRequestHandle is not null.

Fix http://b/issue?id=1980031

core/java/android/webkit/LoadListener.java

@@ -410,7 +410,8 @@ class LoadListener extends Handler implements EventHandler {
                 mStatusCode == HTTP_MOVED_PERMANENTLY ||
                 mStatusCode == HTTP_TEMPORARY_REDIRECT) && 
                 mNativeLoader != 0) {
-            if (!mFromCache && URLUtil.isNetworkUrl(mUrl)) {
+            if (!mFromCache && mRequestHandle != null
+                    && !mRequestHandle.getMethod().equals("POST")) {
                 mCacheResult = CacheManager.createCacheFile(mUrl, mStatusCode,
                         headers, mMimeType, false);
             }