Add platform/transforms pretty printers for logging and testing

third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp

Index: third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp
diff --git a/third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp b/third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp
index a0815f8d667b3957f105e1b412a81ec3d419a0cc..3a804e1e13469a5407fe393a9f0e5fa677bf25d8 100644
--- a/third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp
+++ b/third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp
@@ -37,6 +37,7 @@
 
 #include "wtf/Assertions.h"
 #include "wtf/MathExtras.h"
+#include "wtf/text/WTFString.h"
 
 #include <cmath>
 #include <cstdlib>
@@ -1598,4 +1599,33 @@ SkMatrix44 TransformationMatrix::toSkMatrix44(const TransformationMatrix& matrix
     return ret;
 }
 
+String TransformationMatrix::toString(bool asMatrix) const
+{
+    if (asMatrix) {
+        // Return as a matrix in row-major order.
+        return String::format("[%lg,%lg,%lg,%lg,\n%lg,%lg,%lg,%lg,\n%lg,%lg,%lg,%lg,\n%lg,%lg,%lg,%lg]",
+            m11(), m21(), m31(), m41(),
+            m12(), m22(), m32(), m42(),
+            m13(), m23(), m33(), m43(),
+            m14(), m24(), m34(), m44());
+    }
+
+    TransformationMatrix::DecomposedType decomposition;
+    if (!decompose(decomposition))
+        return "degenerate";

[jbroman, 2016/08/21 16:21:07]

nit: maybe the matrix representation above would be more helpful in this case.
Or possibly even both:

return toString(true) + " (degenerate)";

[pdr., 2016/08/22 17:27:35]

Good idea, done.

+
+    if (isIdentityOrTranslation()) {
+        if (decomposition.translateX == 0 && decomposition.translateY == 0 && decomposition.translateZ == 0)
+            return "identity";
+        return String::format("translation(%lg,%lg,%lg)", decomposition.translateX, decomposition.translateY, decomposition.translateZ);
+    }
+
+    return String::format("translation(%lg,%lg,%lg), scale(%lg,%lg,%lg), skew(%lg,%lg,%lg), quaternion(%lg,%lg,%lg,%lg), perspective(%lg,%lg,%lg,%lg)",
+        decomposition.translateX, decomposition.translateY, decomposition.translateZ,
+        decomposition.scaleX, decomposition.scaleY, decomposition.scaleZ,
+        decomposition.skewXY, decomposition.skewXZ, decomposition.skewYZ,
+        decomposition.quaternionX, decomposition.quaternionY, decomposition.quaternionZ, decomposition.quaternionW,
+        decomposition.perspectiveX, decomposition.perspectiveY, decomposition.perspectiveZ, decomposition.perspectiveW);
+}
+
 } // namespace blink