Refactor viewport initialization logic out of WebViewImpl.

Source/core/page/PageScaleConstraints.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 10 matching lines @@
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef Composition_h
-#define Composition_h
+#ifndef PageScaleConstraints_h
+#define PageScaleConstraints_h
 
-#include "wtf/PassRefPtr.h"
-#include "wtf/RefCounted.h"
-#include "wtf/RefPtr.h"
+#include "core/platform/graphics/FloatSize.h"
 
 namespace WebCore {
 
-class Node;
-class Range;
+struct PageScaleConstraints {
+    FloatSize layoutSize;
 
-class Composition : public RefCounted<Composition> {
-public:
-    static PassRefPtr<Composition> create(Node*, Range*);
-    ~Composition();
+    float initialScale;
+    float minimumScale;
+    float maximumScale;
 
-    Node* text() const { return m_text.get(); }
-    Range* caret() const { return m_caret.get(); }
+    PageScaleConstraints();
+    PageScaleConstraints(float initial, float minimum, float maximum);
 
-private:
-    Composition(Node*, Range*);
+    void overrideWith(const PageScaleConstraints& other);
+    float clampToConstraints(float pageScaleFactor) const;
+    void clampAll();
+    void fitToContentsWidth(float contentsWidth, int viewWidthNotIncludingScrollbars);
 
-    RefPtr<Node> m_text;
-    RefPtr<Range> m_caret;
+    bool operator==(const PageScaleConstraints& other) const;
 };
 
 } // namespace WebCore
 
-#endif // Composition_h
+#endif // PageScaleConstraints_h