Associate native MeasuredText with Java one.

To measure text beforehand, remove static layout dependency from
MeasuredText. Now MeasuredText can compute native measured text
by itself and StaticLayout use it for line breaking.

This CL introduce one additional JNI method call per paragraph during
line breaking but looks negligible cost.

Here is a raw performance test result on walleye-userdebug.

StaticLayoutPerfTest (median, N=100):
createRandom:          7,879,440 -> 7,964,789 (+1.08%)
createRandom Balanced: 7,835,192 -> 7,848,151 (+0.17%)

TextViewOnMeasurePerfTest (median, N=100):
measure_AtMost:       92,599,175 ->  93,027,121 (+0.47%)
measure_Exactly:      89,949,922 ->  90,439,886 (+0.54%)
measure_Unspecified: 148,645,916 -> 150,047,694 (+0.94%)

Bug: 67504091
Test: bit CtsTextTestCases:*
Test: bit CtsWidgetTestCases:*
Test: bit CtsGraphicsTestCases:*
Test: bit FrameworksCoreTests:android.text.StaticLayoutTest
Change-Id: Ie932903845645e50cfa0cb428babb31a44babc47
diff --git a/core/java/android/text/StaticLayout.java b/core/java/android/text/StaticLayout.java
index 81c82c9..400b075 100644
--- a/core/java/android/text/StaticLayout.java
+++ b/core/java/android/text/StaticLayout.java
@@ -48,6 +48,18 @@
  * Canvas.drawText()} directly.</p>
  */
 public class StaticLayout extends Layout {
+    /*
+     * The break iteration is done in native code. The protocol for using the native code is as
+     * follows.
+     *
+     * First, call nInit to setup native line breaker object. Then, for each paragraph, do the
+     * following:
+     *
+     *   - Create MeasuredText by MeasuredText.buildForStaticLayout which measures in native.
+     *   - Run nComputeLineBreaks() to obtain line breaks for the paragraph.
+     *
+     * After all paragraphs, call finish() to release expensive buffers.
+     */
 
     static final String TAG = "StaticLayout";
 
@@ -724,10 +736,11 @@
                 }
 
                 measured = MeasuredText.buildForStaticLayout(
-                        paint, source, paraStart, paraEnd, textDir, nativePtr, measured);
+                        paint, source, paraStart, paraEnd, textDir, measured);
                 final char[] chs = measured.getChars();
                 final int[] spanEndCache = measured.getSpanEndCache().getRawArray();
                 final int[] fmCache = measured.getFontMetrics().getRawArray();
+                // TODO: Stop keeping duplicated width copy in native and Java.
                 widths.resize(chs.length);
 
                 // measurement has to be done before performing line breaking
@@ -739,6 +752,7 @@
 
                         // Inputs
                         chs,
+                        measured.getNativePtr(),
                         paraEnd - paraStart,
                         firstWidth,
                         firstWidthLineCount,
@@ -873,18 +887,14 @@
 
             if ((bufEnd == bufStart || source.charAt(bufEnd - 1) == CHAR_NEW_LINE)
                     && mLineCount < mMaximumVisibleLineCount) {
-                measured = MeasuredText.buildForStaticLayout(
-                        paint, source, bufEnd, bufEnd, textDir, nativePtr, measured);
-
                 paint.getFontMetricsInt(fm);
-
                 v = out(source,
                         bufEnd, bufEnd, fm.ascent, fm.descent,
                         fm.top, fm.bottom,
                         v,
                         spacingmult, spacingadd, null,
                         null, fm, 0,
-                        needMultiply, measured, bufEnd,
+                        needMultiply, null, bufEnd,
                         includepad, trackpad, addLastLineSpacing, null,
                         null, bufStart, ellipsize,
                         ellipsizedWidth, 0, paint, false);
@@ -902,7 +912,7 @@
     private int out(final CharSequence text, final int start, final int end, int above, int below,
             int top, int bottom, int v, final float spacingmult, final float spacingadd,
             final LineHeightSpan[] chooseHt, final int[] chooseHtv, final Paint.FontMetricsInt fm,
-            final int flags, final boolean needMultiply, final MeasuredText measured,
+            final int flags, final boolean needMultiply, @Nullable final MeasuredText measured,
             final int bufEnd, final boolean includePad, final boolean trackPad,
             final boolean addLastLineLineSpacing, final char[] chs, final float[] widths,
             final int widthStart, final TextUtils.TruncateAt ellipsize, final float ellipsisWidth,
@@ -911,7 +921,7 @@
         final int off = j * mColumns;
         final int want = off + mColumns + TOP;
         int[] lines = mLines;
-        final int dir = measured.getParagraphDir();
+        final int dir = (start == end) ? Layout.DIR_LEFT_TO_RIGHT : measured.getParagraphDir();
 
         if (want >= lines.length) {
             final int[] grow = ArrayUtils.newUnpaddedIntArray(GrowingArrayUtils.growSize(want));
@@ -938,7 +948,11 @@
         lines[off + TAB] |= flags & TAB_MASK;
         lines[off + HYPHEN] = flags;
         lines[off + DIR] |= dir << DIR_SHIFT;
-        mLineDirections[j] = measured.getDirections(start - widthStart, end - widthStart);
+        if (start == end) {
+            mLineDirections[j] = Layout.DIRS_ALL_LEFT_TO_RIGHT;
+        } else {
+            mLineDirections[j] = measured.getDirections(start - widthStart, end - widthStart);
+        }
 
         final boolean firstLine = (j == 0);
         final boolean currentLineIsTheLastVisibleOne = (j + 1 == mMaximumVisibleLineCount);
@@ -1415,33 +1429,6 @@
                 mMaxLineHeight : super.getHeight();
     }
 
-    /**
-     * Measurement and break iteration is done in native code. The protocol for using
-     * the native code is as follows.
-     *
-     * First, call nInit to setup native line breaker object. Then, for each paragraph, do the
-     * following:
-     *
-     *   - Call one of the following methods for each run within the paragraph depending on the type
-     *     of run:
-     *     + addStyleRun (a text run, to be measured in native code)
-     *     + addReplacementRun (a replacement run, width is given)
-     *
-     *   - Run nComputeLineBreaks() to obtain line breaks for the paragraph.
-     *
-     * After all paragraphs, call finish() to release expensive buffers.
-     */
-
-    /* package */ static void addStyleRun(long nativePtr, TextPaint paint, int start, int end,
-            boolean isRtl) {
-        nAddStyleRun(nativePtr, paint.getNativeInstance(), start, end, isRtl);
-    }
-
-    /* package */ static void addReplacementRun(long nativePtr, TextPaint paint, int start, int end,
-            float width) {
-        nAddReplacementRun(nativePtr, paint.getNativeInstance(), start, end, width);
-    }
-
     @FastNative
     private static native long nInit(
             @BreakStrategy int breakStrategy,
@@ -1454,17 +1441,6 @@
     @CriticalNative
     private static native void nFinish(long nativePtr);
 
-    @CriticalNative
-    private static native void nAddStyleRun(
-            /* non-zero */ long nativePtr, /* non-zero */ long nativePaint,
-            @IntRange(from = 0) int start, @IntRange(from = 0) int end, boolean isRtl);
-
-    @CriticalNative
-    private static native void nAddReplacementRun(
-            /* non-zero */ long nativePtr, /* non-zero */ long nativePaint,
-            @IntRange(from = 0) int start, @IntRange(from = 0) int end,
-            @FloatRange(from = 0.0f) float width);
-
     // populates LineBreaks and returns the number of breaks found
     //
     // the arrays inside the LineBreaks objects are passed in as well
@@ -1477,6 +1453,7 @@
 
             // Inputs
             @NonNull char[] text,
+            /* Non Zero */ long measuredTextPtr,
             @IntRange(from = 0) int length,
             @FloatRange(from = 0.0f) float firstWidth,
             @IntRange(from = 0) int firstWidthLineCount,