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

chrome/browser/printing/print_preview_dialog_controller.cc

Index: chrome/browser/printing/print_preview_dialog_controller.cc
diff --git a/chrome/browser/printing/print_preview_dialog_controller.cc b/chrome/browser/printing/print_preview_dialog_controller.cc
index 6211d5c39e99661f74f0542e1160510e06b3018d..19b350146c2c2def6c364ec7bffb0c249b4d0a95 100644
--- a/chrome/browser/printing/print_preview_dialog_controller.cc
+++ b/chrome/browser/printing/print_preview_dialog_controller.cc
@@ -78,9 +78,7 @@ 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 {
@@ -99,10 +97,16 @@ void PrintPreviewDialogDelegate::GetWebUIMessageHandlers(
 
 void PrintPreviewDialogDelegate::GetDialogSize(gfx::Size* size) const {
   DCHECK(size);
-  const gfx::Size kMinDialogSize(800, 480);
   const int kBorder = 25;
+// Gives ChromeOS dialogs the requested minimum size of 438x455 without changing
+// the existing behavior on Mac OSX. For all other platforms, the min size
+// is later overriden by the size of the parent window.

[Lei Zhang, 2016/08/18 20:30:57]

overridden?

[rbpotter, 2016/08/19 01:59:09]

Done.

+#if defined(OS_MACOSX)
+  const gfx::Size kMinDialogSize(800, 480);
+#else
+  const gfx::Size kMinDialogSize(438, 455);

[Lei Zhang, 2016/08/18 20:30:57]

So no behavior changes on Windows/Linux, right?

[rbpotter, 2016/08/19 01:59:09]

There will be no behavior changes in terms of the minimum size - it will still
shrink to the size of the parent window. The only thing that might change is
that it will keep its border within the parent window a little longer - once the
parent window gets small enough that the minimum size gets ignored the dialog
goes almost to the edge of the parent window since it no longer has its border.
Is this a problem?

[Lei Zhang, 2016/08/19 03:28:46]

No, seems ok.

+#endif
   *size = kMinDialogSize;
-
   web_modal::WebContentsModalDialogHost* host = nullptr;
   content::WebContents* outermost_web_contents =
       guest_view::GuestViewBase::GetTopLevelWebContents(initiator_);
@@ -114,8 +118,15 @@ void PrintPreviewDialogDelegate::GetDialogSize(gfx::Size* size) const {
     size->SetToMax(host->GetMaximumDialogSize());
   else
     size->SetToMax(outermost_web_contents->GetContainerBounds().size());
+#if defined(OS_MACOSX)
   size->Enlarge(-2 * kBorder, -kBorder);
-
+#else
+  int expand_width =
+      std::min(size->width() - kMinDialogSize.width(), 2 * kBorder);
+  int expand_height =
+      std::min(size->height() - kMinDialogSize.height(), kBorder);
+  size->Enlarge(-expand_width, -expand_height);

[Lei Zhang, 2016/08/18 20:30:57]

Why not just calculate |expand_width| so it's negative in the first place? And
rename to shrink_width?

[rbpotter, 2016/08/19 01:59:09]

Done. I thought it was more readable to take the minimum of the desired  border
and the remaining size rather than doing a max of two negative values, and
renaming to "shrink" while making them negative would seem like we are shrinking
by a negative amount, when really we are expanding by a negative amount.

[Lei Zhang, 2016/08/19 03:28:46]

*shrug* If you like it better the other way, feel free to go back.

+#endif
 #if defined(OS_MACOSX)
   // Limit the maximum size on MacOS X.
   // http://crbug.com/105815
@@ -365,10 +376,9 @@ WebContents* PrintPreviewDialogController::CreatePrintPreviewDialog(
 
   // The dialog delegates are deleted when the dialog is closed.
   ConstrainedWebDialogDelegate* web_dialog_delegate =
-      ShowConstrainedWebDialog(initiator->GetBrowserContext(),
-                               new PrintPreviewDialogDelegate(initiator),
-                               initiator);
-
+      ShowNonClippedConstrainedWebDialog(
+          initiator->GetBrowserContext(),
+          new PrintPreviewDialogDelegate(initiator), initiator);
   WebContents* preview_dialog = web_dialog_delegate->GetWebContents();
 
   // Clear the zoom level for the print preview dialog so it isn't affected by