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

chrome/browser/resources/pdf/viewport.js

Index: chrome/browser/resources/pdf/viewport.js
diff --git a/chrome/browser/resources/pdf/viewport.js b/chrome/browser/resources/pdf/viewport.js
index 47c25079faaa3b23ee3346b6ddc7f68f3f4c7b43..04e34d4715b8b62b8eb009e759ee0384e23c9b55 100644
--- a/chrome/browser/resources/pdf/viewport.js
+++ b/chrome/browser/resources/pdf/viewport.js
@@ -45,6 +45,7 @@ function Viewport(window,
   this.scrollbarWidth_ = scrollbarWidth;
   this.fittingType_ = Viewport.FittingType.NONE;
   this.defaultZoom_ = defaultZoom;
+  this.topToolbarHeight = 0;

[Sam McNally, 2015/08/03 08:06:45]

Please make this a constructor param instead of a public attribute.

[raymes, 2015/08/04 00:28:46]

Done.

 
   window.addEventListener('scroll', this.updateViewport_.bind(this));
   window.addEventListener('resize', this.resize_.bind(this));
@@ -139,8 +140,8 @@ Viewport.prototype = {
     if (this.documentDimensions_) {
       this.sizer_.style.width =
           this.documentDimensions_.width * this.zoom_ + 'px';
-      this.sizer_.style.height =
-          this.documentDimensions_.height * this.zoom_ + 'px';
+      this.sizer_.style.height = this.documentDimensions_.height * this.zoom_ +
+          this.topToolbarHeight + 'px';
     }
   },
 
@@ -171,7 +172,7 @@ Viewport.prototype = {
   get position() {
     return {
       x: this.window_.pageXOffset,
-      y: this.window_.pageYOffset
+      y: this.window_.pageYOffset - this.topToolbarHeight
     };
   },
 
@@ -180,7 +181,7 @@ Viewport.prototype = {
    * @type {Object} position the position to scroll to.
    */
   set position(position) {
-    this.window_.scrollTo(position.x, position.y);
+    this.window_.scrollTo(position.x, position.y + this.topToolbarHeight);
   },
 
   /**
@@ -229,15 +230,17 @@ Viewport.prototype = {
             'Viewport.mightZoom_.';
     }
     // Record the scroll position (relative to the top-left of the window).
-    var currentScrollPos = [
-      this.window_.pageXOffset / this.zoom_,
-      this.window_.pageYOffset / this.zoom_
-    ];
+    var currentScrollPos = {
+      x: this.position.x / this.zoom_,
+      y: this.position.y / this.zoom_
+    };
     this.zoom_ = newZoom;
     this.contentSizeChanged_();
     // Scroll to the scaled scroll position.
-    this.window_.scrollTo(currentScrollPos[0] * newZoom,
-                          currentScrollPos[1] * newZoom);
+    this.position = {
+      x: currentScrollPos.x * newZoom,
+      y: currentScrollPos.y * newZoom
+    };
   },
 
   /**
@@ -426,8 +429,12 @@ Viewport.prototype = {
         height: this.pageDimensions_[page].height,
       };
       this.setZoomInternal_(this.computeFittingZoom_(dimensions, false));
-      if (scrollToTopOfPage)
-        this.window_.scrollTo(0, this.pageDimensions_[page].y * this.zoom_);
+      if (scrollToTopOfPage) {
+        this.position = {
+          x: 0,
+          y: this.pageDimensions_[page].y * this.zoom_
+        };
+      }
       this.updateViewport_();
     }.bind(this));
   },
@@ -485,8 +492,15 @@ Viewport.prototype = {
       if (page >= this.pageDimensions_.length)
         page = this.pageDimensions_.length - 1;
       var dimensions = this.pageDimensions_[page];
-      this.window_.scrollTo(dimensions.x * this.zoom_,
-                            dimensions.y * this.zoom_);
+      var toolbarOffset = 0;
+      // Unless we're in fit to page mode, scroll a bit above the page so that

[Sam McNally, 2015/08/03 08:06:45]

Can you be a bit more precise than "a bit above"?

[raymes, 2015/08/04 00:28:46]

Done.

+      // the toolbar isn't covering it initially.
+      if (this.fittingType_ != Viewport.FittingType.FIT_TO_PAGE)
+        toolbarOffset = this.topToolbarHeight;
+      this.position = {
+        x: dimensions.x * this.zoom_,
+        y: dimensions.y * this.zoom_ - toolbarOffset
+      };
       this.updateViewport_();
     }.bind(this));
   },
@@ -504,7 +518,10 @@ Viewport.prototype = {
         this.setZoomInternal_(
             Math.min(this.defaultZoom_,
                      this.computeFittingZoom_(this.documentDimensions_, true)));
-        this.window_.scrollTo(0, 0);
+        this.position = {
+          x: 0,
+          y: -this.topToolbarHeight
+        };
       }
       this.contentSizeChanged_();
       this.resize_();