Call clearCache on WebView before collecting memory information.

tests/DumpRenderTree/src/com/android/dumprendertree/LoadTestsAutoTest.java

@@ -72,6 +72,7 @@ public class LoadTestsAutoTest extends ActivityInstrumentationTestCase2<TestShel
         // Run tests
         runTestAndWaitUntilDone(activity, runner.mTestPath, runner.mTimeoutInMillis);
 
+        activity.clearCache();
         dumpMemoryInfo();
 
         // Kill activity

tests/DumpRenderTree/src/com/android/dumprendertree/TestShellActivity.java

@@ -87,6 +87,10 @@ public class TestShellActivity extends Activity implements LayoutTestController
         }
     }
 
+    public void clearCache() {
+      mWebView.clearCache(true);
+    }
+
     @Override
     protected void onCreate(Bundle icicle) {
         super.onCreate(icicle);