Cleanups related to SkFixed.

This CL relands https://codereview.chromium.org/1683743005/ with two fixes:
  - Removing the test for vertical text. Vertical text doesn't work on Windows and breakText isn't supported for non-trivial text.
  - Omit PaintBreakTextTest in Google3 because we don't have the correct font setup yet.

Remove SK_FixedNaN. It does not seem to be supported or used anywhere in Skia, Chromium, Android, or Google3, (except accidentally by TwoPtRadial::kDontDrawT). I think supporting it would erase any benefit of SkFixed over float.

Remove SkBitmapFilter::lookup. It does not appear to be used anywhere in Skia, Chromium, Android, or Google3.

Fix a bug in SkPaint::breakText that limited it to ~5kB of text. Now it can handle more than 1GB.

BUG=skia:4632
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1683743005

Committed: https://skia.googlesource.com/skia/+/7ea5cb18389db11a94175de95c9db2b44972630c

patch from issue 1683743005 at patchset 120001 (http://crrev.com/1683743005#ps120001)

Review URL: https://codereview.chromium.org/1739453002

1 files changed, 84 insertions, 0 deletions

diff --git a/tests/PaintBreakTextTest.cpp b/tests/PaintBreakTextTest.cpp
new file mode 100644
index 0000000000..474bbf686a
--- /dev/null
+++ b/tests/PaintBreakTextTest.cpp
@@ -0,0 +1,84 @@
+/*
+ * Copyright 2011-2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkPaint.h"
+#include "Test.h"
+
+static void test_monotonic(skiatest::Reporter* reporter,
+                           const SkPaint& paint,
+                           const char* msg) {
+    const char* text = "sdfkljAKLDFJKEWkldfjlk#$%&sdfs.dsj";
+    const size_t length = strlen(text);
+    const SkScalar width = paint.measureText(text, length);
+
+    SkScalar mm = 0;
+    size_t nn = 0;
+    const SkScalar step = SkMaxScalar(width / 10, SK_Scalar1);
+    for (SkScalar w = 0; w <= width; w += step) {
+        SkScalar m;
+        const size_t n = paint.breakText(text, length, w, &m);
+
+        REPORTER_ASSERT_MESSAGE(reporter, n <= length, msg);
+        REPORTER_ASSERT_MESSAGE(reporter, m <= width, msg);
+
+        if (n == 0) {
+            REPORTER_ASSERT_MESSAGE(reporter, m == 0, msg);
+        } else {
+            // now assert that we're monotonic
+            if (n == nn) {
+                REPORTER_ASSERT_MESSAGE(reporter, m == mm, msg);
+            } else {
+                REPORTER_ASSERT_MESSAGE(reporter, n > nn, msg);
+                REPORTER_ASSERT_MESSAGE(reporter, m > mm, msg);
+            }
+        }
+        nn = n;
+        mm = m;
+    }
+}
+
+static void test_eq_measure_text(skiatest::Reporter* reporter,
+                                 const SkPaint& paint,
+                                 const char* msg) {
+    const char* text = "The ultimate measure of a man is not where he stands in moments of comfort "
+        "and convenience, but where he stands at times of challenge and controversy.";
+    const size_t length = strlen(text);
+    const SkScalar width = paint.measureText(text, length);
+
+    SkScalar mm;
+    const size_t length2 = paint.breakText(text, length, width, &mm);
+    REPORTER_ASSERT_MESSAGE(reporter, length2 == length, msg);
+    REPORTER_ASSERT_MESSAGE(reporter, mm == width, msg);
+}
+
+static void test_long_text(skiatest::Reporter* reporter,
+                           const SkPaint& paint,
+                           const char* msg) {
+    static const int kSize = 16 * 1024;
+    SkAutoMalloc block(kSize);
+    memset(block.get(), 'a', kSize - 1);
+    char* text = static_cast<char*>(block.get());
+    text[kSize - 1] = '\0';
+    const SkScalar width = paint.measureText(text, kSize);
+
+    SkScalar mm;
+    const size_t length = paint.breakText(text, kSize, width, &mm);
+    REPORTER_ASSERT_MESSAGE(reporter, length == kSize, msg);
+    REPORTER_ASSERT_MESSAGE(reporter, mm == width, msg);
+}
+
+DEF_TEST(PaintBreakText, reporter) {
+    SkPaint paint;
+    test_monotonic(reporter, paint, "default");
+    test_eq_measure_text(reporter, paint, "default");
+    test_long_text(reporter, paint, "default");
+    paint.setTextSize(SkIntToScalar(1 << 17));
+    test_monotonic(reporter, paint, "huge text size");
+    test_eq_measure_text(reporter, paint, "huge text size");
+    paint.setTextSize(0);
+    test_monotonic(reporter, paint, "zero text size");
+}