SF: Remove display config functions from HWC2

HWC2 is unnecessary stateful stopgap between HWComposer and
ComposerHal. In this CL the following functions are removed from HWC2
  * getActiveConfig
  * getActiveConfigIndex
  * getDisplayVsyncPeriod

and ComposerHal is called directly from HWComposer. This way display
configs are stored only in HWComposer.

Additionally HWC2::Display::Config is renamed to DisplayMode and
it's extracted in its own file.

From the perspective of SurfaceFlinger this CL is not modifying
behaviour.

Bug: 159590486
Bug: 175678215
Test: atest libsurfaceflinger_unittest
Change-Id: I8cb450209adf038d891cff00d1c2690c8e6d94f7
diff --git a/services/surfaceflinger/DisplayHardware/DisplayMode.h b/services/surfaceflinger/DisplayHardware/DisplayMode.h
new file mode 100644
index 0000000..69fd00e
--- /dev/null
+++ b/services/surfaceflinger/DisplayHardware/DisplayMode.h
@@ -0,0 +1,131 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "DisplayHardware/Hal.h"
+#include "Scheduler/HwcStrongTypes.h"
+
+#include <android/configuration.h>
+#include <utils/Timers.h>
+
+#include <memory>
+#include <vector>
+
+namespace android {
+
+namespace hal = android::hardware::graphics::composer::hal;
+
+class DisplayMode;
+using DisplayModePtr = std::shared_ptr<const DisplayMode>;
+using DisplayModes = std::vector<DisplayModePtr>;
+
+class DisplayMode {
+public:
+    class Builder {
+    public:
+        explicit Builder(hal::HWConfigId id) : mDisplayMode(new DisplayMode(id)) {}
+
+        DisplayModePtr build() {
+            return std::const_pointer_cast<const DisplayMode>(std::move(mDisplayMode));
+        }
+
+        Builder& setId(HwcConfigIndexType id) {
+            mDisplayMode->mId = id;
+            return *this;
+        }
+
+        Builder& setWidth(int32_t width) {
+            mDisplayMode->mWidth = width;
+            return *this;
+        }
+
+        Builder& setHeight(int32_t height) {
+            mDisplayMode->mHeight = height;
+            return *this;
+        }
+
+        Builder& setVsyncPeriod(int32_t vsyncPeriod) {
+            mDisplayMode->mVsyncPeriod = vsyncPeriod;
+            return *this;
+        }
+
+        Builder& setDpiX(int32_t dpiX) {
+            if (dpiX == -1) {
+                mDisplayMode->mDpiX = getDefaultDensity();
+            } else {
+                mDisplayMode->mDpiX = dpiX / 1000.0f;
+            }
+            return *this;
+        }
+
+        Builder& setDpiY(int32_t dpiY) {
+            if (dpiY == -1) {
+                mDisplayMode->mDpiY = getDefaultDensity();
+            } else {
+                mDisplayMode->mDpiY = dpiY / 1000.0f;
+            }
+            return *this;
+        }
+
+        Builder& setConfigGroup(int32_t configGroup) {
+            mDisplayMode->mConfigGroup = configGroup;
+            return *this;
+        }
+
+    private:
+        float getDefaultDensity() {
+            // Default density is based on TVs: 1080p displays get XHIGH density, lower-
+            // resolution displays get TV density. Maybe eventually we'll need to update
+            // it for 4k displays, though hopefully those will just report accurate DPI
+            // information to begin with. This is also used for virtual displays and
+            // older HWC implementations, so be careful about orientation.
+
+            auto longDimension = std::max(mDisplayMode->mWidth, mDisplayMode->mHeight);
+            if (longDimension >= 1080) {
+                return ACONFIGURATION_DENSITY_XHIGH;
+            } else {
+                return ACONFIGURATION_DENSITY_TV;
+            }
+        }
+        std::shared_ptr<DisplayMode> mDisplayMode;
+    };
+
+    HwcConfigIndexType getId() const { return mId; }
+    hal::HWConfigId getHwcId() const { return mHwcId; }
+
+    int32_t getWidth() const { return mWidth; }
+    int32_t getHeight() const { return mHeight; }
+    nsecs_t getVsyncPeriod() const { return mVsyncPeriod; }
+    float getDpiX() const { return mDpiX; }
+    float getDpiY() const { return mDpiY; }
+    int32_t getConfigGroup() const { return mConfigGroup; }
+
+private:
+    explicit DisplayMode(hal::HWConfigId id) : mHwcId(id) {}
+
+    hal::HWConfigId mHwcId;
+    HwcConfigIndexType mId;
+
+    int32_t mWidth = -1;
+    int32_t mHeight = -1;
+    nsecs_t mVsyncPeriod = -1;
+    float mDpiX = -1;
+    float mDpiY = -1;
+    int32_t mConfigGroup = -1;
+};
+
+} // namespace android
\ No newline at end of file