Add a scroll offset to PDF documents to account for the top material design toolbar.

chrome/test/data/pdf/viewport_test.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var tests = [
   function testDocumentNeedsScrollbars() {
     var viewport =
         new Viewport(new MockWindow(100, 100), new MockSizer(), function() {},
                      function() {}, function() {}, 10, 1);
     var scrollbars;
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   },
 
   function testInitialSetDocumentDimensionsZoomUnconstrained() {
     var viewport = new Viewport(
         new MockWindow(100, 100),
         new MockSizer(), function() {}, function() {}, function() {}, 0, 3);
     viewport.setDocumentDimensions(new MockDocumentDimensions(50, 50));
     chrome.test.assertEq(2, viewport.zoom);
     chrome.test.succeed();
   },
+
+  function testToolbarHeightOffset() {
+    var mockSizer = new MockSizer();
+    var mockWindow = new MockWindow(100, 100);
+    var viewport = new Viewport(mockWindow,
+        mockSizer, function() {}, function() {}, function() {}, 0, 1);
+    viewport.topToolbarHeight = 50;
+    var documentDimensions = new MockDocumentDimensions(0, 0);
+    documentDimensions.addPage(50, 500);
+    viewport.setDocumentDimensions(documentDimensions);
+    viewport.setZoom(1);
+
+    // Check that the sizer incorporates the toolbar height.
+    chrome.test.assertEq('550px', mockSizer.style.height);
+    chrome.test.assertEq('50px', mockSizer.style.width);
+    chrome.test.assertEq(0, viewport.position.x);
+
+    // Check the sizer incorporates the toolbar height correctly even if zoomed.
+    viewport.setZoom(2);
+    chrome.test.assertEq('1050px', mockSizer.style.height);
+    chrome.test.assertEq('100px', mockSizer.style.width);
+
+    // Test that the viewport scrolls to the correct offset when fit-to-page is
+    // enabled. The top of the viewport should be at the start of the document.
+    viewport.fitToPage();
+    chrome.test.assertEq(0, viewport.position.y);
+
+    // Check that going to a page scrolls to the correct offset when fit-to-page
+    // is enabled. The top of the viewport should be at the start of the
+    // document.
+    mockWindow.scrollTo(0, 100);
+    viewport.goToPage(0);
+    chrome.test.assertEq(0, viewport.position.y);
+
+    // Check that going to a page scrolls to the correct offset when fit-to-page
+    // is not enabled. The top of the viewport should be before start of the
+    // document.
+    viewport.setZoom(1);
+    viewport.goToPage(0);
+    chrome.test.assertEq(-50, viewport.position.y);
+    chrome.test.succeed();
+  }
 ];
 
 chrome.test.runTests(tests);