Propagate browser zoom changes to embedded PDFs.

chrome/browser/resources/pdf/pdf.js

Index: chrome/browser/resources/pdf/pdf.js
diff --git a/chrome/browser/resources/pdf/pdf.js b/chrome/browser/resources/pdf/pdf.js
index 14aebcf8cdd755cb52ca1a871027d8acf8bc1c35..357b9c4c19a35f5a86e31b8fae478bfbf3eda8f2 100644
--- a/chrome/browser/resources/pdf/pdf.js
+++ b/chrome/browser/resources/pdf/pdf.js
@@ -137,7 +137,7 @@ function PDFViewer(browserApi) {
                                 this.beforeZoom_.bind(this),
                                 this.afterZoom_.bind(this),
                                 getScrollbarWidth(),
-                                this.browserApi_.getDefaultZoom(),
+                                this.browserApi_.getInitialZoom(),

[raymes, 2016/11/17 00:59:57]

Hmm, how come you're changing this to InitialZoom rather than DefaultZoom?
+sammc who fixed some bugs around this.

[Sam McNally, 2016/11/18 04:59:23]

The reason for the default zoom was for PDFs we want to zoom the PDF to fit the
page, but not zoom in more than the default zoom level. As the comment for
lookupInitialZoom() says, this isn't always the same as the zoom level of the
tab.

This should still be the default zoom for top-level PDFs, and either the default
zoom or default zoom * initial zoom for embedded PDFs.

[Kevin McNee, 2016/11/22 23:17:32]

Right. If the tab the pdf is in has been zoomed, we want the pdf to start off
zoomed as well.

[Sam McNally, 2016/11/28 07:25:13]

For non-embedded PDFs we still want to use the default zoom here.

[Kevin McNee, 2016/11/28 16:18:44]

Yes, if it's not embedded, we set the zoom mode to manual, which resets the zoom
level to the default. So the initial zoom is equal to the default zoom. But for
clarity, I can change it back.

[Kevin McNee, 2016/11/28 17:03:32]

Done.

                                 topToolbarHeight);
 
   // Create the plugin object dynamically so we can set its src. The plugin
@@ -230,7 +230,7 @@ function PDFViewer(browserApi) {
       new ToolbarManager(window, this.toolbar_, this.zoomToolbar_);
 
   // Set up the ZoomManager.
-  this.zoomManager_ = new ZoomManager(
+  this.zoomManager_ = ZoomManager.create(this.browserApi_.getZoomBehaviour(),
       this.viewport_, this.browserApi_.setZoom.bind(this.browserApi_),
       this.browserApi_.getInitialZoom());
   this.browserApi_.addZoomEventListener(