Implement a basic PPAPI plugin for Blink layout tests.

ppapi/tests/blink_test_plugin.cc

Index: ppapi/tests/blink_test_plugin.cc
diff --git a/ppapi/tests/blink_test_plugin.cc b/ppapi/tests/blink_test_plugin.cc
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+++ b/ppapi/tests/blink_test_plugin.cc
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+// Copyright 2015 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 <sstream>
+#include <utility>
+
+#include "ppapi/cpp/completion_callback.h"
+#include "ppapi/cpp/graphics_2d.h"
+#include "ppapi/cpp/image_data.h"
+#include "ppapi/cpp/input_event.h"
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/module.h"
+
+namespace {
+
+void DummyCompletionCallback(void*, int32_t) {}
+
+// This is a simple C++ Pepper plugin for Blink layout tests.
+//
+// Layout tests can instantiate this plugin by requesting the mime type
+// application/x-blink-test-plugin. When possible, tests should use the
+// startAfterLoadAndFinish() helper in resources/plugin.js to perform work
+// after the plugin has loaded.
+//
+// The plugin also exposes several other features for testing convenience:
+// - On first paint, the plugin posts a 'loaded' message to its owner element.
+// - On subsequent paints, the plugin posts a 'painted' message instead.
+// - Keyboard and mouse input events are logged to the console.
+class BlinkTestInstance : public pp::Instance {
+ public:
+  explicit BlinkTestInstance(PP_Instance instance)
+      : pp::Instance(instance), first_paint_(true) {}
+  ~BlinkTestInstance() override {}
+
+  bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
+    return RequestFilteringInputEvents(PP_INPUTEVENT_CLASS_MOUSE |
+                                       PP_INPUTEVENT_CLASS_KEYBOARD) == PP_OK;
+  }
+
+  void DidChangeView(const pp::View& view) override {
+    view_ = view;
+    device_context_ = pp::Graphics2D(this, view_.GetRect().size(), true);
+    if (!BindGraphics(device_context_))
+      return;
+
+    // Since we draw a static image, we only need to make a new frame when
+    // the device is initialized or the view size changes.
+    Paint();
+  }
+
+  void DidChangeFocus(bool has_focus) override {
+    LogMessage("DidChangeFocus(", has_focus, ")");
+  }
+
+  bool HandleInputEvent(const pp::InputEvent& event) override {
+    switch (event.GetType()) {
+      case PP_INPUTEVENT_TYPE_MOUSEDOWN:
+        LogMouseEvent("Down", event);
+        break;
+      case PP_INPUTEVENT_TYPE_MOUSEUP:
+        LogMouseEvent("Up", event);
+        break;
+      case PP_INPUTEVENT_TYPE_KEYDOWN:
+        LogKeyboardEvent("Down", event);
+        break;
+      case PP_INPUTEVENT_TYPE_KEYUP:
+        LogKeyboardEvent("Up", event);
+        break;
+      case PP_INPUTEVENT_TYPE_MOUSEMOVE:
+      case PP_INPUTEVENT_TYPE_MOUSEENTER:
+      case PP_INPUTEVENT_TYPE_MOUSELEAVE:
+      case PP_INPUTEVENT_TYPE_RAWKEYDOWN:
+      case PP_INPUTEVENT_TYPE_CHAR:
+        // Just swallow these events without any logging.
+        return true;
+      default:
+        LogMessage("Unexpected input event with type = ", event.GetType());
+        return false;
+    }
+    return true;
+  }
+
+ private:
+  void Paint() {
+    pp::ImageData image(this, PP_IMAGEDATAFORMAT_BGRA_PREMUL,
+                        view_.GetRect().size(), true);
+    if (image.is_null())
+      return;
+
+    // Draw blue and green checkerboard pattern to show "interesting" keyframe.
+    const int kSquareSizePixels = 8;
+    for (int y = 0; y < view_.GetRect().size().height(); ++y) {
+      for (int x = 0; x < view_.GetRect().size().width(); ++x) {
+        int x_square = x / kSquareSizePixels;
+        int y_square = y / kSquareSizePixels;
+        uint32_t color = ((x_square + y_square) % 2) ? 0xFF0000FF : 0xFF00FF00;
+        *image.GetAddr32(pp::Point(x, y)) = color;
+      }
+    }
+
+    device_context_.ReplaceContents(&image);
+    device_context_.Flush(
+        pp::CompletionCallback(&DummyCompletionCallback, nullptr));
+
+    // TODO(dcheng): In theory, this should wait for the flush to complete
+    // before claiming that it's painted. In practice, this is difficult: when
+    // running layout tests, a frame is typically only generated at the end of
+    // the layout test. Sending the completion message in the callback results
+    // in a deadlock: the test wants to wait for the plugin to paint, but the
+    // plugin won't paint until the test completes. This seems to be Good
+    // Enough™ for now.
+    if (first_paint_) {
+      first_paint_ = false;
+      PostMessage(pp::Var("loaded"));
+    } else {
+      PostMessage(pp::Var("painted"));
+    }
+  }
+
+  void LogMouseEvent(const std::string& type, const pp::InputEvent& event) {
+    pp::MouseInputEvent mouse_event(event);
+    pp::Point mouse_position = mouse_event.GetPosition();
+    LogMessage("Mouse", type, " at (", mouse_position.x(), ",",
+               mouse_position.y(), ")");
+  }
+
+  void LogKeyboardEvent(const std::string& type, const pp::InputEvent& event) {
+    pp::KeyboardInputEvent keyboard_event(event);
+    LogMessage("Key", type, " '", keyboard_event.GetCode().AsString(), "'");
+  }
+
+  // Template magic to cover the lack of base::StringPrintf.
+  template <typename... Args>
+  void LogMessage(const Args&... args) {
+    std::ostringstream ss;
+    ss << std::boolalpha;
+    LogMessageHelper(&ss, args...);
+  }
+
+  template <typename Arg, typename... Args>
+  void LogMessageHelper(std::ostringstream* os,
+                        const Arg& arg,
+                        const Args&... args) {
+    *os << arg;
+    LogMessageHelper(os, args...);
+  }
+
+  template <typename Arg>
+  void LogMessageHelper(std::ostringstream* os, const Arg& arg) {
+    *os << arg;
+    LogToConsoleWithSource(PP_LOGLEVEL_LOG, pp::Var("Blink Test Plugin"),
+                           pp::Var(os->str()));
+  }
+
+  bool first_paint_;
+  pp::View view_;
+  pp::Graphics2D device_context_;
+};
+
+class BlinkTestModule : public pp::Module {
+ public:
+  BlinkTestModule() {}
+  virtual ~BlinkTestModule() {}
+
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new BlinkTestInstance(instance);
+  }
+};
+
+}  // namespace
+
+namespace pp {
+
+Module* CreateModule() {
+  return new BlinkTestModule();
+}
+
+}  // namespace pp