[PDF Ink Signatures] Make test support functions broadly accessible

Move some test support functions out of pdf_ink_transform_unittest.cc
and into pdf/ink/ink_affine_transform.h, so that they can be used by
other test files.

Low-Coverage-Reason: TRIVIAL_CHANGE Function moves, and the uncovered function is only executed for test failures
Change-Id: If5affff3fcd58b0df2893a4c316e8f50feb9de4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5632106
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Alan Screen <awscreen@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1315603}

pdf/ink/BUILD.gn

@@ -23,6 +23,7 @@ source_set("interface") {
   visibility = [ "//pdf/*" ]
 
   sources = [
+    "ink_affine_transform.cc",
     "ink_affine_transform.h",
     "ink_brush.h",
     "ink_brush_behavior.h",

pdf/ink/ink_affine_transform.cc

@@ -0,0 +1,22 @@
+// Copyright 2024 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "pdf/ink/ink_affine_transform.h"
+
+#include <ostream>
+
+namespace chrome_pdf {
+
+bool operator==(const InkAffineTransform& lhs, const InkAffineTransform& rhs) {
+  return lhs.a == rhs.a && lhs.b == rhs.b && lhs.c == rhs.c && lhs.d == rhs.d &&
+         lhs.e == rhs.e && lhs.f == rhs.f;
+}
+
+void PrintTo(const InkAffineTransform& transform, std::ostream* os) {
+  *os << "[ " << transform.a << ", " << transform.b << ", " << transform.c
+      << ", " << transform.d << ", " << transform.e << ", " << transform.f
+      << " ]";
+}
+
+}  // namespace chrome_pdf

pdf/ink/ink_affine_transform.h

@@ -5,6 +5,8 @@
 #ifndef PDF_INK_INK_AFFINE_TRANSFORM_H_
 #define PDF_INK_INK_AFFINE_TRANSFORM_H_
 
+#include <iosfwd>
+
 namespace chrome_pdf {
 
 // NOTE: This is the equivalent to the following 3x3 matrix:
@@ -23,6 +25,11 @@ struct InkAffineTransform {
   float f;
 };
 
+bool operator==(const InkAffineTransform& lhs, const InkAffineTransform& rhs);
+
+// Supports pretty-printing transforms for test failures.
+void PrintTo(const InkAffineTransform& transform, std::ostream* os);
+
 }  // namespace chrome_pdf
 
 #endif  // PDF_INK_INK_AFFINE_TRANSFORM_H_

pdf/pdf_ink_transform_unittest.cc

@@ -72,18 +72,6 @@ struct InputOutputPair {
 
 }  // namespace
 
-bool operator==(const InkAffineTransform& lhs, const InkAffineTransform& rhs) {
-  return lhs.a == rhs.a && lhs.b == rhs.b && lhs.c == rhs.c && lhs.d == rhs.d &&
-         lhs.e == rhs.e && lhs.f == rhs.f;
-}
-
-// Supports pretty-printing transforms for test failures.
-void PrintTo(const InkAffineTransform& transform, std::ostream* os) {
-  *os << base::StringPrintf("[ %f, %f, %f, %f, %f, %f ]", transform.a,
-                            transform.b, transform.c, transform.d, transform.e,
-                            transform.f);
-}
-
 TEST(PdfInkTransformTest, EventPositionToCanonicalPositionIdentity) {
   constexpr auto kInputsAndOutputs = std::to_array<InputOutputPair>({
       InputOutputPair{kInputPositionTopLeft, kCanonicalPositionTopLeft},