Prevent LayoutTest setting -1 page scale factor.

third_party/WebKit/Source/core/testing/Internals.cpp

Index: third_party/WebKit/Source/core/testing/Internals.cpp
diff --git a/third_party/WebKit/Source/core/testing/Internals.cpp b/third_party/WebKit/Source/core/testing/Internals.cpp
index 5420021b8ae163c2b7c9301edd74d4f079612e0b..81cfd730be6f005f1c8046781db9011928180900 100644
--- a/third_party/WebKit/Source/core/testing/Internals.cpp
+++ b/third_party/WebKit/Source/core/testing/Internals.cpp
@@ -1878,6 +1878,10 @@ float Internals::pageScaleFactor(ExceptionState& exceptionState)
 
 void Internals::setPageScaleFactor(float scaleFactor, ExceptionState& exceptionState)
 {
+    // -1 is the initial value of page scale factor in blink, it should never be
+    // set by external methods.
+    if (scaleFactor == -1)

[bokan, 2016/09/20 17:32:09]

it's not the initial value. It's a value used by the various limits (minimum,
maximum, initial-scale) but never page scale factor. Just make this `if
(scaleFactor <= 0) return;`, no need for a comment.

[sunxd, 2016/09/20 17:47:10]

Done.

+        return;
     Document* document = contextDocument();
     if (!document || !document->page()) {
         exceptionState.throwDOMException(InvalidAccessError, document ? "The document's page cannot be retrieved." : "No context document can be obtained.");