Basic display management for mus

components/mus/ws/platform_screen_ozone.cc

+// Copyright 2016 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 "components/mus/ws/platform_screen.h"
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/sys_info.h"
+#include "base/thread_task_runner_handle.h"
+#include "ui/display/types/display_snapshot.h"
+#include "ui/display/types/native_display_delegate.h"
+#include "ui/ozone/public/ozone_platform.h"
+
+namespace mus {
+namespace ws {
+
+PlatformScreen::PlatformScreen()
+    : is_configuring_(false),
+      should_configure_(false),
+      weak_ptr_factory_(this) {}
+
+PlatformScreen::~PlatformScreen() {}
+
+void PlatformScreen::Init() {
+  native_display_delegate_ =
+      ui::OzonePlatform::GetInstance()->CreateNativeDisplayDelegate();
+  native_display_delegate_->AddObserver(this);
+  native_display_delegate_->Initialize();
+}
+
+// TODO(rjkroege): Remove this code once ozone oxygen has the same
+// display creation semantics as ozone drm.
+void PlatformScreen::FixedSizeScreenConfiguration(
+    ConfiguredDisplayCallback callback) {
+  callback.Run(1, gfx::Rect(1024, 768));
+}
+
+void PlatformScreen::ConfigurePhysicalDisplay(
+    ConfiguredDisplayCallback callback) {
+  callback_ = callback;
+
+  if (base::SysInfo::IsRunningOnChromeOS()) {
+    // Kick off the configuration of the physical displays comprising the
+    // |PlatformScreen|
+    OnConfigurationChanged();
+  } else {
+    // PostTask()ed to maximize control flow similarity with the ChromeOS case.
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(&PlatformScreen::FixedSizeScreenConfiguration,
+                              weak_ptr_factory_.GetWeakPtr(), callback));
+  }
+}
+
+// TODO(rjkroege): Support multiple displays.
+// The display subsystem tells us that the display configuration has changed on
+// the first and subsequent change in display parameters. We have to kick this
+// off manually the first time.
+void PlatformScreen::OnConfigurationChanged() {
+  DCHECK(native_display_delegate_) << "DefaultDisplayManager::"
+                                      "OnConfigurationChanged requires a "
+                                      "native_display_delegate_ to work.";
+  if (callback_.is_null()) {

[sky, 2016/05/03 02:39:51]

nit: no {}

[rjkroege, 2016/05/03 21:03:04]

Done.

+    return;
+  }
+  if (is_configuring_) {

[sky, 2016/05/03 02:39:51]

nit: no {}

[rjkroege, 2016/05/03 21:03:04]

Done.

+    should_configure_ = true;
+  }
+  is_configuring_ = true;
+  native_display_delegate_->GrabServer();
+  native_display_delegate_->GetDisplays(
+      base::Bind(&PlatformScreen::OnDisplaysAquired,
+                 weak_ptr_factory_.GetWeakPtr(), callback_));

[sky, 2016/05/03 02:39:51]

Why do you need both a member for the callback and pass the callback around?

[rjkroege, 2016/05/03 21:03:04]

OnConfigurationChanged() implements  NativeDisplayObserver so the callback can't
be passed into this function. Passing the callback around internally henceforth
means that multiple calls to ConfigurePhysicalDisplay() will each invoke the
provided callback.

+}
+
+// The display subsystem calls |OnDisplaysAquired| to deliver |displays|
+// describing the attached displays.
+void PlatformScreen::OnDisplaysAquired(
+    ConfiguredDisplayCallback callback,
+    const std::vector<ui::DisplaySnapshot*>& displays) {
+  DCHECK(native_display_delegate_) << "DefaultDisplayManager::"
+                                      "OnConfigurationChanged requires a "
+                                      "native_display_delegate_ to work.";
+  CHECK(displays.size() == 1) << "Mus only supports one 1 display\n";
+  gfx::Point origin;
+  for (auto display : displays) {
+    if (!display->native_mode()) {
+      LOG(ERROR) << "Display " << display->display_id()
+                 << " doesn't have a native mode";
+      continue;
+    }
+    // Setup each native display. This places a task on the DRM thread's
+    // runqueue that configures the window size correctly before the call to
+    // Configure.
+    native_display_delegate_->Configure(
+        *display, display->native_mode(), origin,
+        base::Bind(&PlatformScreen::OnDisplayConfigured,
+                   weak_ptr_factory_.GetWeakPtr(), callback,
+                   display->display_id(),
+                   gfx::Rect(origin, display->native_mode()->size())));
+    origin.Offset(display->native_mode()->size().width(), 0);
+  }
+  native_display_delegate_->UngrabServer();
+  is_configuring_ = false;
+  if (should_configure_) {
+    should_configure_ = false;
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(&PlatformScreen::OnConfigurationChanged,
+                              weak_ptr_factory_.GetWeakPtr()));
+  }
+}
+
+// The display subsystem calls  |OnDisplayConfigured| for each display that has
+// been successfully configured. This in turn calls |callback_| with the
+// identity
+// and bounds of each physical display.
+void PlatformScreen::OnDisplayConfigured(ConfiguredDisplayCallback callback,
+                                         int64_t id,
+                                         const gfx::Rect& bounds,
+                                         bool success) {
+  if (success)
+    callback.Run(id, bounds);
+  else
+    LOG(FATAL) << "Failed to configure display at " << bounds.ToString();
+}
+
+}  // namespace ws
+}  // namespace mus