[WebRTC] Add ScreenCapturerDifferWrapper to share Differ across ScreenCapturers

webrtc/modules/desktop_capture/screen_capturer_mock_objects.cc

Index: webrtc/modules/desktop_capture/screen_capturer_mock_objects.cc
diff --git a/webrtc/modules/desktop_capture/screen_capturer_mock_objects.cc b/webrtc/modules/desktop_capture/screen_capturer_mock_objects.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1f712ab7e9b012ffb600ccf2824f7827fe3d290b
--- /dev/null
+++ b/webrtc/modules/desktop_capture/screen_capturer_mock_objects.cc
@@ -0,0 +1,135 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/desktop_capture/screen_capturer_mock_objects.h"
+
+#include <stdint.h>
+#include <string.h>
+
+#include <utility>
+
+#include "webrtc/base/random.h"
+#include "webrtc/base/timeutils.h"
+#include "webrtc/modules/desktop_capture/shared_desktop_frame.h"
+
+namespace webrtc {
+
+namespace {
+
+// Creates a DesktopFrame according to the input |factory|, and paints it to
+// white.
+std::unique_ptr<DesktopFrame> CreateDesktopFrame(
+    DesktopSize size,
+    SharedMemoryFactory* factory) {
+  std::unique_ptr<DesktopFrame> frame(
+      factory ?
+      SharedMemoryDesktopFrame::Create(size, factory).release() :
+      new BasicDesktopFrame(size));
+  memset(frame->data(), 0, frame->stride() * frame->size().height());
+  return SharedDesktopFrame::Wrap(std::move(frame));
+}
+
+// Paints pixels in |rect| of |frame| to |color|.
+void PaintRect(DesktopFrame* frame, DesktopRect rect, uint32_t color) {
+  static_assert(DesktopFrame::kBytesPerPixel == sizeof(uint32_t),
+                "kBytesPerPixel should be 4.");
+  ASSERT_TRUE(frame->size().width() >= rect.width() &&
+              frame->size().height() >= rect.height());
+  int row = rect.top() * frame->stride();
+  for (int i = 0; i < rect.height(); i++) {
+    int column = rect.left() * DesktopFrame::kBytesPerPixel;
+    for (int j = 0; j < rect.width(); j++) {
+      memcpy(&frame->data()[row + column], &color, sizeof(color));
+      column += DesktopFrame::kBytesPerPixel;
+    }
+    row += frame->stride();
+  }
+}
+
+// Paints pixels in |region| of |frame| to |color|.
+void PaintRegion(DesktopFrame* frame,
+                 const DesktopRegion& region,
+                 uint32_t color) {
+  for (DesktopRegion::Iterator it(region); !it.IsAtEnd(); it.Advance()) {
+    PaintRect(frame, it.rect(), color);
+  }
+}
+
+// Sets dirty region of |frame| to |dirty_region|. If |enlarge_dirty_region| is
+// true, this function will randomly enlarge each DesktopRect in |dirty_region|.
+// But the enlarged DesktopRegion won't excceed the frame->size().
+void SetDirtyRegion(DesktopFrame* frame,
+                    const DesktopRegion& dirty_region,
+                    bool enlarge_dirty_region) {
+  DesktopRect screen_rect = DesktopRect::MakeSize(frame->size());
+  Random random(rtc::TimeMicros());
+  frame->mutable_updated_region()->Clear();
+  for (DesktopRegion::Iterator it(dirty_region); !it.IsAtEnd(); it.Advance()) {
+    DesktopRect rect = it.rect();
+    if (enlarge_dirty_region) {
+      rect = DesktopRect::MakeLTRB(rect.left() - random.Rand(20),
+                                   rect.top() - random.Rand(20),
+                                   rect.right() + random.Rand(20),
+                                   rect.bottom() + random.Rand(20));
+      rect.IntersectWith(screen_rect);
+    }
+    frame->mutable_updated_region()->AddRect(rect);
+  }
+}
+
+}  // namespace
+
+MockScreenCapturer::MockScreenCapturer()
+    : callback_(nullptr),
+      size_(1024, 768),
+      result_(Result::SUCCESS),
+      return_frame_(true),
+      provide_dirty_region_hints_(false),
+      enlarge_dirty_region_(false) {
+  ON_CALL(*this, Start(testing::_))
+      .WillByDefault(testing::Invoke([this](Callback* callback) {
+        callback_ = callback;
+      }));
+
+  ON_CALL(*this, Capture(testing::_))
+      .WillByDefault(testing::Invoke([this](const DesktopRegion& region) {
+        // A typical ScreenCapturer won't use the |region| parameter.
+        ASSERT_TRUE(callback_);
+        if (return_frame_) {
+          std::unique_ptr<DesktopFrame> frame =
+              CreateDesktopFrame(size_, shared_memory_factory_.get());
+          PaintRegion(frame.get(), dirty_region_, UINT32_MAX);
+          if (provide_dirty_region_hints_) {
+            SetDirtyRegion(frame.get(), dirty_region_, enlarge_dirty_region_);
+          }
+          dirty_region_.Clear();
+          callback_->OnCaptureResult(result_, std::move(frame));
+        } else {
+          callback_->OnCaptureResult(result_, std::unique_ptr<DesktopFrame>());
+        }
+      }));
+
+  ON_CALL(*this, GetScreenList(testing::_))
+      .WillByDefault(testing::Return(true));
+
+  ON_CALL(*this, SelectScreen(testing::_))
+      .WillByDefault(testing::Invoke([](ScreenId id) {
+        return id == kFullDesktopScreenId;
+      }));
+}
+
+MockScreenCapturer::~MockScreenCapturer() = default;
+
+void MockScreenCapturer::SetSharedMemoryFactory(
+    std::unique_ptr<SharedMemoryFactory> shared_memory_factory) {
+  shared_memory_factory_ = std::move(shared_memory_factory);
+}
+
+}  // namespace webrtc