Need to clear viewport dependent units switching print mode.

third_party/WebKit/Source/web/tests/WebViewTest.cpp

Index: third_party/WebKit/Source/web/tests/WebViewTest.cpp
diff --git a/third_party/WebKit/Source/web/tests/WebViewTest.cpp b/third_party/WebKit/Source/web/tests/WebViewTest.cpp
index 0840d8c1b77fabff9833895c78e37f803c92c267..5801086b7986c9ec458142638bfec882042a01e8 100644
--- a/third_party/WebKit/Source/web/tests/WebViewTest.cpp
+++ b/third_party/WebKit/Source/web/tests/WebViewTest.cpp
@@ -89,6 +89,7 @@
 #include "public/web/WebFrameContentDumper.h"
 #include "public/web/WebHitTestResult.h"
 #include "public/web/WebInputMethodController.h"
+#include "public/web/WebPrintParams.h"
 #include "public/web/WebScriptSource.h"
 #include "public/web/WebSettings.h"
 #include "public/web/WebTreeScopeType.h"
@@ -4283,4 +4284,33 @@ TEST_P(WebViewTest, ViewportOverrideAdaptsToScaleAndScroll) {
             *devToolsEmulator->visibleContentRectForPainting());
 }
 
+TEST_P(WebViewTest, ResizeForPrintingViewportUnits) {
+  WebViewImpl* webView = m_webViewHelper.initialize();
+  webView->resize(WebSize(800, 600));
+
+  WebURL baseURL = URLTestHelpers::toKURL("http://example.com/");
+  FrameTestHelpers::loadHTMLString(webView->mainFrame(),
+                                   "<style>#vw { width: 100vw }</style>"
+                                   "<div id=vw></div>",
+                                   baseURL);
+
+  WebLocalFrameImpl* frame = webView->mainFrameImpl();
+  Document* document = frame->frame()->document();
+  Element* vwElement = document->getElementById("vw");
+
+  EXPECT_EQ(800, vwElement->offsetWidth());
+
+  WebPrintParams printParams;
+  printParams.printContentArea.width = 500;
+  printParams.printContentArea.height = 500;
+
+  frame->printBegin(printParams, WebNode());
+  webView->resize(WebSize(500, 500));
+  EXPECT_EQ(500, vwElement->offsetWidth());
+
+  webView->resize(WebSize(800, 600));
+  frame->printEnd();
+  EXPECT_EQ(800, vwElement->offsetWidth());
+}
+
 }  // namespace blink