Fix high-DPI on Windows to make use of DIP scaling in WebKit.

content/browser/renderer_host/render_widget_host_view_win.cc

Index: content/browser/renderer_host/render_widget_host_view_win.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_win.cc b/content/browser/renderer_host/render_widget_host_view_win.cc
index 152a51fcce93175428e06a0f5940dbb22cf42fd0..3630b58078c22a7ad03093b0a96d6030d4d29717 100644
--- a/content/browser/renderer_host/render_widget_host_view_win.cc
+++ b/content/browser/renderer_host/render_widget_host_view_win.cc
@@ -52,6 +52,7 @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebCompositionUnderline.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/win/WebInputEventFactory.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/win/WebScreenInfoFactory.h"
 #include "ui/base/events/event.h"
 #include "ui/base/events/event_utils.h"
 #include "ui/base/ime/composition_text.h"
@@ -61,6 +62,7 @@
 #include "ui/base/touch/touch_device_win.h"
 #include "ui/base/ui_base_switches.h"
 #include "ui/base/view_prop.h"
+#include "ui/base/win/dpi.h"
 #include "ui/base/win/hwnd_util.h"
 #include "ui/base/win/mouse_wheel_util.h"
 #include "ui/gfx/canvas.h"
@@ -300,6 +302,17 @@ bool ShouldSendPinchGesture() {
   return pinch_allowed;
 }
 
+void GetScreenInfoForWindow(WebKit::WebScreenInfo* results,
+                            gfx::NativeViewId id) {
+  *results = WebKit::WebScreenInfoFactory::screenInfo(
+      gfx::NativeViewFromId(id));
+#if defined(ENABLE_HIDPI)
+  results->deviceScaleFactor = ui::win::GetDeviceScaleFactor();

[darin (slow to review), 2013/01/30 21:39:12]

Wouldn't it be better to provide ui::win::GetDeviceScaleFactor() when
ENABLE_HIDPI is not defined?  Just make it return 1.  Then, you can probably
have less #ifdef'ing in the code, right?

[kevers, 2013/01/30 22:27:01]

Removed the #ifdef, as GetDeviceScaleFactor always returns 1 when high-DPI is
not enabled.

+#else
+  results->deviceScaleFactor = 1;
+#endif
+}
+
 }  // namespace
 
 const wchar_t kRenderWidgetHostHWNDClass[] = L"Chrome_RenderWidgetHostHWND";
@@ -464,7 +477,7 @@ void RenderWidgetHostViewWin::WasHidden() {
 }
 
 void RenderWidgetHostViewWin::SetSize(const gfx::Size& size) {
-  SetBounds(gfx::Rect(GetViewBounds().origin(), size));
+  SetBounds(gfx::Rect(GetPixelBounds().origin(), size));
 }
 
 void RenderWidgetHostViewWin::SetBounds(const gfx::Rect& rect) {
@@ -597,6 +610,10 @@ bool RenderWidgetHostViewWin::IsShowing() {
 }
 
 gfx::Rect RenderWidgetHostViewWin::GetViewBounds() const {
+  return ui::win::ScreenToDIPRect(GetPixelBounds());
+}
+
+gfx::Rect RenderWidgetHostViewWin::GetPixelBounds() const {
   CRect window_rect;
   GetWindowRect(&window_rect);
   return gfx::Rect(window_rect);
@@ -697,7 +714,7 @@ void RenderWidgetHostViewWin::Redraw() {
 
   // Send the invalid rect in screen coordinates.
   gfx::Rect invalid_screen_rect(damage_bounds);
-  invalid_screen_rect.Offset(GetViewBounds().OffsetFromOrigin());
+  invalid_screen_rect.Offset(GetPixelBounds().OffsetFromOrigin());
 
   PaintPluginWindowsHelper(m_hWnd, invalid_screen_rect);
 }
@@ -2363,6 +2380,10 @@ void RenderWidgetHostViewWin::AcceleratedPaint(HDC dc) {
     accelerated_surface_->Present(dc);
 }
 
+void RenderWidgetHostViewWin::GetScreenInfo(WebKit::WebScreenInfo* results) {
+  GetScreenInfoForWindow(results, GetNativeViewId());
+}
+
 gfx::Rect RenderWidgetHostViewWin::GetBoundsInRootWindow() {
   RECT window_rect = {0};
   HWND root_window = GetAncestor(m_hWnd, GA_ROOT);
@@ -2377,7 +2398,9 @@ gfx::Rect RenderWidgetHostViewWin::GetBoundsInRootWindow() {
     rect.Inset(GetSystemMetrics(SM_CXSIZEFRAME),
                GetSystemMetrics(SM_CYSIZEFRAME));
   }
-  return rect;
+
+  // Convert to DIP
+  return ui::win::ScreenToDIPRect(rect);
 }
 
 // Creates a HWND within the RenderWidgetHostView that will serve as a host
@@ -2722,6 +2745,14 @@ void RenderWidgetHostViewWin::ForwardMouseEventToRenderer(UINT message,
     return;
   }
 
+#if defined(ENABLE_HIDPI)

[darin (slow to review), 2013/01/30 21:39:12]

Why do we need ENABLE_HIDPI?  Why not just have all of the math equate to
identify functions when not in HI-DPI mode?

[kevers, 2013/01/30 22:27:01]

The ScreenToDPIPoint is an identity function when not in high-DPI mode.  Was
erring on the side of caution for a feature that is currently in development. 
Can remove the #ifdef.

+  // Convert to DIP
+  gfx::Point point = ui::win::ScreenToDIPPoint(
+      gfx::Point(static_cast<short>(LOWORD(lparam)),
+                 static_cast<short>(HIWORD(lparam))));
+  lparam = (point.y() << 16) + point.x();
+#endif
+
   WebMouseEvent event(
       WebInputEventFactory::mouseEvent(m_hWnd, message, wparam, lparam));
 
@@ -2974,7 +3005,7 @@ LRESULT RenderWidgetHostViewWin::OnQueryCharPosition(
   }
   ClientToScreen(&target_rect);
 
-  RECT document_rect = GetViewBounds().ToRECT();
+  RECT document_rect = GetPixelBounds().ToRECT();
   ClientToScreen(&document_rect);
 
   position->pt.x = target_rect.left;
@@ -3018,4 +3049,10 @@ RenderWidgetHostView* RenderWidgetHostView::CreateViewForWidget(
   return new RenderWidgetHostViewWin(widget);
 }
 
+// static
+void RenderWidgetHostViewPort::GetDefaultScreenInfo(
+      WebKit::WebScreenInfo* results) {
+  GetScreenInfoForWindow(results, 0);
+}
+
 }  // namespace content