Use SkASSERTResult to avoid unused local variables

tools/viewer/sk_app/android/surface_glue_android.cpp

Index: tools/viewer/sk_app/android/surface_glue_android.cpp
diff --git a/tools/viewer/sk_app/android/surface_glue_android.cpp b/tools/viewer/sk_app/android/surface_glue_android.cpp
index e8715582c096c02c3c1e0ad0b77cc90095c14150..9e35407255f8956eea8d1496692d7684886a4ede 100644
--- a/tools/viewer/sk_app/android/surface_glue_android.cpp
+++ b/tools/viewer/sk_app/android/surface_glue_android.cpp
@@ -77,13 +77,11 @@ void SkiaAndroidApp::paintIfNeeded() {
 }
 
 void SkiaAndroidApp::postMessage(const Message& message) const {
-    auto writeSize = write(fPipes[1], &message, sizeof(message));
-    SkASSERT(writeSize == sizeof(message));
+    SkAssertResult(write(fPipes[1], &message, sizeof(message)) == sizeof(message));
 }
 
 void SkiaAndroidApp::readMessage(Message* message) const {
-    auto readSize = read(fPipes[0], message, sizeof(Message));
-    SkASSERT(readSize == sizeof(Message));
+    SkAssertResult(read(fPipes[0], message, sizeof(Message)) == sizeof(Message));

[egdaniel, 2016/05/20 18:50:23]

So just doing a fly by unsolicited review. Here would it be better to have just
surrounded the "auto read/writeSize =" in SkDEBUGCODE(...) so we don't do the
compare on release?

[liyuqian, 2016/05/20 18:53:00]

That's a good point. However, I've already committed the change... Shall I
create another CL?

 }
 
 void SkiaAndroidApp::inval() {