Support InputMethodManager#updateCursorAnchorInfo for Android 5.0

ui/android/java/src/org/chromium/ui/base/CursorAnchorInfoBuilder.java

+// Copyright 2014 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.
+
+package org.chromium.ui.base;
+
+import android.graphics.Matrix;
+import android.os.Build;
+import android.view.inputmethod.CursorAnchorInfo;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+
+import java.lang.CharSequence;
+
+/**
+ * A simple class to allow native code to call instance methods of {@link CursorAnchorInfo.Builder}.
+ * This class itself is designed to be stateless. All the methods are thread-safe.
+ */
+@JNINamespace("ui")
+public final class CursorAnchorInfoBuilder {
+
+    private static final Matrix sMatrix = new Matrix();
+    private static final float[] sMatrixValues = new float[9];
+
+    @CalledByNative
+    public static CursorAnchorInfo.Builder create() {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            return null;
+        }
+        return new CursorAnchorInfo.Builder();
+    }
+
+    @CalledByNative
+    public static void reset(CursorAnchorInfo.Builder builder) {
+        if (builder == null) {
+            return;
+        }
+        builder.reset();
+    }
+
+    @CalledByNative
+    public static void setSelectionRange(CursorAnchorInfo.Builder builder, int newStart,
+            int newEnd) {
+        if (builder == null) {

[jdduke (slow), 2015/01/14 17:17:09]

Hmm, when will the builder be null? Can we avoid making these calls in such
case?

[yukawa, 2015/01/14 22:21:58]

Basically |builder| shouldn't be null.  Removed accordingly.

+            return;
+        }
+        builder.setSelectionRange(newStart, newEnd);
+    }
+
+    @CalledByNative
+    public static void setComposingText(CursorAnchorInfo.Builder builder, int composingTextStart,
+            CharSequence composingText) {
+        if (builder == null) {
+            return;
+        }
+        builder.setComposingText(composingTextStart, composingText);
+    }
+
+    @CalledByNative
+    public static void setInsertionMarkerLocation(CursorAnchorInfo.Builder builder,
+            float horizontalPosition, float lineTop, float lineBaseline, float lineBottom,
+            int flags) {
+        if (builder == null) {
+            return;
+        }
+        builder.setInsertionMarkerLocation(horizontalPosition, lineTop, lineBaseline, lineBottom,
+                flags);
+    }
+
+    @CalledByNative
+    public static void addCharacterBounds(CursorAnchorInfo.Builder builder, int index, float left,
+            float top, float right, float bottom, int flags) {
+        if (builder == null) {
+            return;
+        }
+        builder.addCharacterBounds(index, left, top, right, bottom, flags);
+    }
+
+    @CalledByNative
+    public static void setMatrix(CursorAnchorInfo.Builder builder, float m00, float m01, float m02,

[jdduke (slow), 2015/01/14 17:17:09]

Would it be simpler to instead just pass the scale/translation components? Then
use the |setScale|, |setTranslate| methods on the matrix?

[yukawa, 2015/01/14 22:21:59]

Done.

+            float m10, float m11, float m12, float m20, float m21, float m22) {
+        if (builder == null) {
+            return;
+        }
+        synchronized (sMatrix) {
+            sMatrixValues[0] = m00;
+            sMatrixValues[1] = m01;
+            sMatrixValues[2] = m02;
+            sMatrixValues[3] = m10;
+            sMatrixValues[4] = m11;
+            sMatrixValues[5] = m12;
+            sMatrixValues[6] = m20;
+            sMatrixValues[7] = m21;
+            sMatrixValues[8] = m22;
+            sMatrix.setValues(sMatrixValues);
+            builder.setMatrix(sMatrix);
+        }
+    }
+
+    @CalledByNative
+    public static CursorAnchorInfo build(CursorAnchorInfo.Builder builder) {
+        if (builder == null) {
+            return null;
+        }
+        return builder.build();
+    }
+}