Created min size for print preview dialog and modified to allow the

chrome/browser/printing/print_preview_dialog_controller.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/printing/print_preview_dialog_controller.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 60 matching lines @@
 };
 
 PrintPreviewDialogDelegate::PrintPreviewDialogDelegate(WebContents* initiator)
     : initiator_(initiator) {
 }
 
 PrintPreviewDialogDelegate::~PrintPreviewDialogDelegate() {
 }
 
 ui::ModalType PrintPreviewDialogDelegate::GetDialogModalType() const {
-  // Not used, returning dummy value.
-  NOTREACHED();
-  return ui::MODAL_TYPE_WINDOW;
+  return ui::MODAL_TYPE_CHILD;
 }
 
 base::string16 PrintPreviewDialogDelegate::GetDialogTitle() const {
   // Only used on Windows? UI folks prefer no title.
   return base::string16();
 }
 
 GURL PrintPreviewDialogDelegate::GetDialogContentURL() const {
   return GURL(chrome::kChromeUIPrintURL);
 }
 
 void PrintPreviewDialogDelegate::GetWebUIMessageHandlers(
     std::vector<WebUIMessageHandler*>* /* handlers */) const {
   // PrintPreviewUI adds its own message handlers.
 }
 
 void PrintPreviewDialogDelegate::GetDialogSize(gfx::Size* size) const {
   DCHECK(size);
-  const gfx::Size kMinDialogSize(800, 480);
+  // Modified to match requested size. Previously: 800, 480.
+  const gfx::Size kMinDialogSize(438, 455);
   const int kBorder = 25;
   *size = kMinDialogSize;
 
   web_modal::WebContentsModalDialogHost* host = nullptr;
   content::WebContents* outermost_web_contents =
       guest_view::GuestViewBase::GetTopLevelWebContents(initiator_);
   Browser* browser = chrome::FindBrowserWithWebContents(outermost_web_contents);
   if (browser)
     host = browser->window()->GetWebContentsModalDialogHost();
 
   if (host)
     size->SetToMax(host->GetMaximumDialogSize());
   else
     size->SetToMax(outermost_web_contents->GetContainerBounds().size());
-  size->Enlarge(-2 * kBorder, -kBorder);
+  int expandWidth = 2*kBorder;

[Lei Zhang, 2016/07/25 21:35:10]

Take a look at the Google C++ style guide. non-const variables are
named_like_this, and there should be spaces around '*'.

[rbpotter, 2016/07/26 21:48:19]

Done.

+  int expandHeight = kBorder;
+  if (size->width() - kMinDialogSize.width() < 2*kBorder) {

[Lei Zhang, 2016/07/25 21:35:10]

This can be combined into:

int expand_width = std::min(size->width() - kMinDialogSize.width(), 2 *
kBorder);

[rbpotter, 2016/07/26 21:48:19]

Done.

+    expandWidth = size->width() - kMinDialogSize.width();
+  }
+  if (size->height() - kMinDialogSize.height() < kBorder) {
+    expandHeight = size->height() - kMinDialogSize.height();
+  }
+  size->Enlarge(-1*expandWidth, -1*expandHeight);

[Lei Zhang, 2016/07/25 21:35:10]

I think you can just write -var instead of -1 * var.

[rbpotter, 2016/07/26 21:48:19]

Done.

 
 #if defined(OS_MACOSX)
   // Limit the maximum size on MacOS X.
   // http://crbug.com/105815
   const gfx::Size kMaxDialogSize(1000, 660);
   size->SetToMin(kMaxDialogSize);
 #endif
 }
 
 std::string PrintPreviewDialogDelegate::GetDialogArgs() const {
@@ skipping 222 matching lines @@
 
   RemoveInitiator(contents);
 }
 
 WebContents* PrintPreviewDialogController::CreatePrintPreviewDialog(
     WebContents* initiator) {
   base::AutoReset<bool> auto_reset(&is_creating_print_preview_dialog_, true);
 
   // The dialog delegates are deleted when the dialog is closed.
   ConstrainedWebDialogDelegate* web_dialog_delegate =
-      ShowConstrainedWebDialog(initiator->GetBrowserContext(),
+      ShowTopLevelConstrainedWebDialog(initiator->GetBrowserContext(),
                                new PrintPreviewDialogDelegate(initiator),

[Mike Wittman, 2016/07/26 17:27:35]

nit: update indendation

                                initiator);
 
   WebContents* preview_dialog = web_dialog_delegate->GetWebContents();
 
   // Clear the zoom level for the print preview dialog so it isn't affected by
   // the default zoom level. This also controls the zoom level of the OOP PDF
   // extension when iframed by the print preview dialog.
   GURL print_url(chrome::kChromeUIPrintURL);
   content::HostZoomMap::Get(preview_dialog->GetSiteInstance())
       ->SetZoomLevelForHostAndScheme(print_url.scheme(), print_url.host(), 0);
@@ skipping 87 matching lines @@
   if (initiator) {
     RemoveObservers(initiator);
     PrintViewManager::FromWebContents(initiator)->PrintPreviewDone();
   }
 
   preview_dialog_map_.erase(preview_dialog);
   RemoveObservers(preview_dialog);
 }
 
 }  // namespace printing