[devtools] Support different encodings for Page.CaptureScreenshot.

ui/snapshot/snapshot_mac.mm

 // 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 "ui/snapshot/snapshot.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/mac/sdk_forward_declarations.h"
 #include "base/task_runner.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/image/image.h"
 
 namespace ui {
 
 bool GrabViewSnapshot(gfx::NativeView view,
                       std::vector<unsigned char>* png_representation,
-                      const gfx::Rect& snapshot_bounds) {
+                      const gfx::Rect& snapshot_bounds,
+                      SnapshotEncoding encoding,
+                      SnapshotQuality quality) {
   NSWindow* window = [view window];
   NSScreen* screen = [[NSScreen screens] firstObject];
   gfx::Rect screen_bounds = gfx::Rect(NSRectToCGRect([screen frame]));
 
 
   // Get the view bounds relative to the screen
   NSRect frame = [view convertRect:[view bounds] toView:nil];
   frame = [window convertRectToScreen:frame];
 
   gfx::Rect view_bounds = gfx::Rect(NSRectToCGRect(frame));
@@ skipping 15 matching lines @@
   base::ScopedCFTypeRef<CGImageRef> windowSnapshot(
       CGWindowListCreateImage(screen_snapshot_bounds.ToCGRect(),
                               kCGWindowListOptionIncludingWindow,
                               [window windowNumber],
                               kCGWindowImageBoundsIgnoreFraming));
   if (CGImageGetWidth(windowSnapshot) <= 0)
     return false;
 
   base::scoped_nsobject<NSBitmapImageRep> rep(
       [[NSBitmapImageRep alloc] initWithCGImage:windowSnapshot]);
-  NSData* data = [rep representationUsingType:NSPNGFileType properties:@{}];
+  NSData* data;
+  float compression_factor = 0;
+  NSDictionary* options = nullptr;
+  switch (encoding) {
+    case SnapshotEncoding::PNG:
+      data = [rep representationUsingType:NSPNGFileType properties:@{}];
+      break;
+    case SnapshotEncoding::JPEG:
+      compression_factor = static_cast<float>(quality) / 100;
+      options = [NSDictionary
+          dictionaryWithObject:[NSNumber numberWithFloat:compression_factor]
+                        forKey:NSImageCompressionFactor];
+      data = [rep representationUsingType:NSJPEGFileType properties:options];
+      break;
+    default:
+      NOTREACHED();
+  }
   const unsigned char* buf = static_cast<const unsigned char*>([data bytes]);
   NSUInteger length = [data length];
   if (buf == NULL || length == 0)
     return false;
 
   png_representation->assign(buf, buf + length);
   DCHECK(!png_representation->empty());
 
   return true;
 }
 
 bool GrabWindowSnapshot(gfx::NativeWindow window,
                         std::vector<unsigned char>* png_representation,
-                        const gfx::Rect& snapshot_bounds) {
+                        const gfx::Rect& snapshot_bounds,
+                        SnapshotEncoding encoding,
+                        SnapshotQuality quality) {
   // Make sure to grab the "window frame" view so we get current tab +
   // tabstrip.
   return GrabViewSnapshot([[window contentView] superview], png_representation,
-      snapshot_bounds);
+                          snapshot_bounds, encoding, quality);
 }
 
 void GrabWindowSnapshotAndScaleAsync(
     gfx::NativeWindow window,
     const gfx::Rect& snapshot_bounds,
     const gfx::Size& target_size,
     scoped_refptr<base::TaskRunner> background_task_runner,
     GrabWindowSnapshotAsyncCallback callback) {
   callback.Run(gfx::Image());
 }
 
 void GrabViewSnapshotAsync(
     gfx::NativeView view,
     const gfx::Rect& source_rect,
     scoped_refptr<base::TaskRunner> background_task_runner,
-    const GrabWindowSnapshotAsyncPNGCallback& callback) {
+    const GrabWindowSnapshotAsyncEncodedCallback& callback,
+    SnapshotEncoding encoding,
+    SnapshotQuality quality) {
   callback.Run(scoped_refptr<base::RefCountedBytes>());
 }
 
 void GrabWindowSnapshotAsync(
     gfx::NativeWindow window,
     const gfx::Rect& source_rect,
     scoped_refptr<base::TaskRunner> background_task_runner,
-    const GrabWindowSnapshotAsyncPNGCallback& callback) {
+    const GrabWindowSnapshotAsyncEncodedCallback& callback,
+    SnapshotEncoding encoding,
+    SnapshotQuality quality) {
   return GrabViewSnapshotAsync([[window contentView] superview], source_rect,
-      background_task_runner, callback);
+                               background_task_runner, callback, encoding,
+                               quality);
 }
 
 }  // namespace ui