Divide InputDispatcher into several files.

This CL does:
1) Isolate implementation details of InputDispatcher from outside and
only expose necessary header files;
2) Move implementation details into android::inputdispatcher namespace;
3) Make input dispatcher a static library for inputflinger to link
against;
4) Add InputDispatcherFactory.{h,cpp} to isolate implementation details
in InputDispatcher.h from InputManager.

Bug: 140139676
Test: Touches on touchscreen can be dispatched to right windows.
Change-Id: Ib61c16fd41f3f76f538a3de9b54f31ac304e03a5
diff --git a/services/inputflinger/dispatcher/InputTarget.h b/services/inputflinger/dispatcher/InputTarget.h
new file mode 100644
index 0000000..5acf92b
--- /dev/null
+++ b/services/inputflinger/dispatcher/InputTarget.h
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+#ifndef _UI_INPUT_INPUTDISPATCHER_INPUTTARGET_H
+#define _UI_INPUT_INPUTDISPATCHER_INPUTTARGET_H
+
+#include <input/InputTransport.h>
+#include <utils/BitSet.h>
+#include <utils/RefBase.h>
+
+namespace android::inputdispatcher {
+
+/*
+ * An input target specifies how an input event is to be dispatched to a particular window
+ * including the window's input channel, control flags, a timeout, and an X / Y offset to
+ * be added to input event coordinates to compensate for the absolute position of the
+ * window area.
+ */
+struct InputTarget {
+    enum {
+        /* This flag indicates that the event is being delivered to a foreground application. */
+        FLAG_FOREGROUND = 1 << 0,
+
+        /* This flag indicates that the MotionEvent falls within the area of the target
+         * obscured by another visible window above it.  The motion event should be
+         * delivered with flag AMOTION_EVENT_FLAG_WINDOW_IS_OBSCURED. */
+        FLAG_WINDOW_IS_OBSCURED = 1 << 1,
+
+        /* This flag indicates that a motion event is being split across multiple windows. */
+        FLAG_SPLIT = 1 << 2,
+
+        /* This flag indicates that the pointer coordinates dispatched to the application
+         * will be zeroed out to avoid revealing information to an application. This is
+         * used in conjunction with FLAG_DISPATCH_AS_OUTSIDE to prevent apps not sharing
+         * the same UID from watching all touches. */
+        FLAG_ZERO_COORDS = 1 << 3,
+
+        /* This flag indicates that the event should be sent as is.
+         * Should always be set unless the event is to be transmuted. */
+        FLAG_DISPATCH_AS_IS = 1 << 8,
+
+        /* This flag indicates that a MotionEvent with AMOTION_EVENT_ACTION_DOWN falls outside
+         * of the area of this target and so should instead be delivered as an
+         * AMOTION_EVENT_ACTION_OUTSIDE to this target. */
+        FLAG_DISPATCH_AS_OUTSIDE = 1 << 9,
+
+        /* This flag indicates that a hover sequence is starting in the given window.
+         * The event is transmuted into ACTION_HOVER_ENTER. */
+        FLAG_DISPATCH_AS_HOVER_ENTER = 1 << 10,
+
+        /* This flag indicates that a hover event happened outside of a window which handled
+         * previous hover events, signifying the end of the current hover sequence for that
+         * window.
+         * The event is transmuted into ACTION_HOVER_ENTER. */
+        FLAG_DISPATCH_AS_HOVER_EXIT = 1 << 11,
+
+        /* This flag indicates that the event should be canceled.
+         * It is used to transmute ACTION_MOVE into ACTION_CANCEL when a touch slips
+         * outside of a window. */
+        FLAG_DISPATCH_AS_SLIPPERY_EXIT = 1 << 12,
+
+        /* This flag indicates that the event should be dispatched as an initial down.
+         * It is used to transmute ACTION_MOVE into ACTION_DOWN when a touch slips
+         * into a new window. */
+        FLAG_DISPATCH_AS_SLIPPERY_ENTER = 1 << 13,
+
+        /* Mask for all dispatch modes. */
+        FLAG_DISPATCH_MASK = FLAG_DISPATCH_AS_IS | FLAG_DISPATCH_AS_OUTSIDE |
+                FLAG_DISPATCH_AS_HOVER_ENTER | FLAG_DISPATCH_AS_HOVER_EXIT |
+                FLAG_DISPATCH_AS_SLIPPERY_EXIT | FLAG_DISPATCH_AS_SLIPPERY_ENTER,
+
+        /* This flag indicates that the target of a MotionEvent is partly or wholly
+         * obscured by another visible window above it.  The motion event should be
+         * delivered with flag AMOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED. */
+        FLAG_WINDOW_IS_PARTIALLY_OBSCURED = 1 << 14,
+
+    };
+
+    // The input channel to be targeted.
+    sp<InputChannel> inputChannel;
+
+    // Flags for the input target.
+    int32_t flags;
+
+    // The x and y offset to add to a MotionEvent as it is delivered.
+    // (ignored for KeyEvents)
+    float xOffset, yOffset;
+
+    // Scaling factor to apply to MotionEvent as it is delivered.
+    // (ignored for KeyEvents)
+    float globalScaleFactor;
+    float windowXScale = 1.0f;
+    float windowYScale = 1.0f;
+
+    // The subset of pointer ids to include in motion events dispatched to this input target
+    // if FLAG_SPLIT is set.
+    BitSet32 pointerIds;
+};
+
+std::string dispatchModeToString(int32_t dispatchMode);
+
+} // namespace android::inputdispatcher
+
+#endif // _UI_INPUT_INPUTDISPATCHER_INPUTTARGET_H