[SVGDom] Improve whitespace handling in style parsing

experimental/svg/model/SkSVGDOM.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvas.h"
 #include "SkDOM.h"
 #include "SkParsePath.h"
@@ skipping 64 matching lines @@
     SkSVGViewBoxType viewBox;
     SkSVGAttributeParser parser(stringValue);
     if (!parser.parseViewBox(&viewBox)) {
         return false;
     }
 
     node->setAttribute(attr, SkSVGViewBoxValue(viewBox));
     return true;
 }
 
+SkString TrimmedString(const char* first, const char* last) {
+    SkASSERT(first);
+    SkASSERT(last);
+    SkASSERT(first <= last);
+
+    while (first <= last && *first <= ' ') { first++; }
+    while (first <= last && *last  <= ' ') { last--; }
+
+    SkASSERT(last - first + 1 >= 0);
+    return SkString(first, SkTo<size_t>(last - first + 1));
+}
+
 // Breaks a "foo: bar; baz: ..." string into key:value pairs.
 class StyleIterator {
 public:
     StyleIterator(const char* str) : fPos(str) { }
 
     std::tuple<SkString, SkString> next() {
         SkString name, value;
 
         if (fPos) {
             const char* sep = this->nextSeparator();
             SkASSERT(*sep == ';' || *sep == '\0');
 
             const char* valueSep = strchr(fPos, ':');
             if (valueSep && valueSep < sep) {
-                name.set(fPos, valueSep - fPos);
-                value.set(valueSep + 1, sep - valueSep - 1);
+                name  = TrimmedString(fPos, valueSep - 1);
+                value = TrimmedString(valueSep + 1, sep - 1);
             }
 
             fPos = *sep ? sep + 1 : nullptr;
         }
 
         return std::make_tuple(name, value);
     }
 
 private:
     const char* nextSeparator() const {
@@ skipping 156 matching lines @@
                                SkSVGLengthContext(fContainerSize),
                                SkSVGPresentationContext());
         fRoot->render(ctx);
     }
 }
 
 void SkSVGDOM::setContainerSize(const SkSize& containerSize) {
     // TODO: inval
     fContainerSize = containerSize;
 }